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Ionic Liquid Mediated Sol Gel Method for Fabrication of

Nanostructured Cerium and Phosphorus Doped TiO2 - A Benign
Photocatalyst: Diversified Applications in Degradation of Dyes and
Microbes
Nageswararao Kadiyala, Siva Rao Tirukkovalluri,* Divya Gorli, Jaishree Genji, Raffiunnisa,
Ravichandra Matangi, and Sai Supriya Singupilla
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ABSTRACT: This work aims to produce semiconductor nanoparticles capable of harnessing visible light for the degradation of dyes
and microbes. Employing an ionic liquid-assisted sol−gel process with varying dopant weight percentages, the study focuses on
crafting Cerium (Ce) and Phosphorus (P) doped TiO2 Nanomaterials. Structural assessments, including Powder X-ray Diffraction
(confirming the anatase phase), Transmission Electron Microscopy (revealing a particle size of 6.2 nm), Brunauer−Emmett−Teller
surface area analysis (yielding 166 m2/gr), and Scanning Electron Microscopy (examining the morphology), were conducted. The
catalysts were further evaluated for optical characteristics: UV−vis diffuse reflectance spectrum (indicating an energy gap of 2.59
eV), Electrochemical Impedance Spectroscopy (with an Efb of −0.30 V), and Valence band XPS (showing Evb at 2.03 eV).
Substitutional doping of dopants into the TiO2 lattice was confirmed through X-ray photoelectron spectroscopy and Fourier
Transform Infra-Red analysis. Photoluminescence Spectrum and Time Correlated Single Photon Counting analysis was employed to
investigate electron−hole recombination. These characterizations suggest the catalysts are effective in degrading microorganisms and
dyes under visible light exposure. Optimal conditions were obtained using CPT5IL2 at pH 3, 0.10 g catalyst dosage, and an initial
dye concentration of 10 mg/L, which were determined to achieve complete dye degradation within 60 min. Furthermore, the
catalyst’s antibacterial and antifungal activity against Enterobacter aerogenes (MTCC-241, Gram-negative), Salmonella typhimurium
(MTCC-98, Gram-negative), and Candida albicans (MTCC-277) were studied.

1. INTRODUCTION production through water-splitting,4 the development of solar

Nanotechnology has enabled the production of materials at the cells,5 energy storage,6 and the photocatalytic degradation of
nanoscale,1 allowing for significant modifications to their organic contaminants and microbes.7 However, despite anatase
chemical and physical properties by altering their molecular TiO2’s ability to absorb ultraviolet light, its effectiveness in the
makeup. The size-dependent qualities of these materials make visible spectrum is limited.
them highly valuable for various applications.2 Recent advance-
ments have shown that fabricating nanomaterials is not only Received: August 21, 2024
essential but also effective in absorbing visible light energy. Revised: December 6, 2024
Among many transition metal oxides, TiO2 stands out as a Accepted: December 13, 2024
unique semiconductor due to its biocompatibility, photo-
stability, nontoxicity, and resistance to photocorrosion.3
Consequently, it has diverse applications, including hydrogen
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Recent studies have shown that doping with metals8,9 or enhanced photocatalysis of P-TiO2 is attributed to the reduced
nonmetals10,11 reduces electron−hole recombination or de- band gap, increased surface oxygen levels (with this excess
creases the band gap, respectively. Jaiswal et al.8 demonstrated oxygen likely being interstitial oxygen near the phosphorus), and
that Vanadium doping boosts photocatalytic efficiency by expanded surface area.39,40
lengthening the lifespan of photogenerated charge pairs. Doping of Cerium and Phosphorus solved the two
According to Jing et al.9 Nickel acts as shallow trapping sites aforementioned constraints of TiO2. Catalysis is a surface
in Ni2+-doped TiO2, significantly increasing the mesoporous phenomenon in which smaller particle sizes result in an increase
photocatalyst’s activity. Ansari et al.10 discovered that Nitrogen- in surface area. When it comes to increasing photocatalytic
doped TiO2 may be used to capture a significant portion of the activity, enhanced surface area41 is preferable in addition to
solar spectrum by decreasing the bandgap of TiO2. Arunmetha doping amounts. Capping agents such as surfactants,42
et al.11 demonstrated that Sulfur doped TiO2 showed better polymers,43 ligands,44 and Ionic Liquids (ILs) can be used to
optical absorption that shifted from the UV to the visible range. limit the agglomeration of particles by encapsulation.
However, only metal doping can induce thermal instability12 Among the capping agents mentioned above, ionic liquids
and increase the recombination rate13,14 when the metal doping (ILs) are a common source of both organic cationic and
is more than 1%.15 Nonmetal doping has some disadvantages, inorganic anionic chemicals. They are also referred to as green
such as reduced catalytic activity and inadequate absorption of solvents or designer solvents.45,46 In order to limit the growth of
visible light.16,17 According to Birlik et al.,18 doping TiO2 with a the nanoparticles and make it easier for particular nanostruc-
single anionic nonmetal may still cause a charge imbalance, tures to form based on various interactions, ILs are stabilizers or
decreasing its photocatalytic efficacy. A single doping of metal or structure-directing agents.47,48 This is caused by (i) the distinct
nonmetal doping is insufficient to either correct electron−hole structure of ILs; a strong electrostatic interaction exists between
recombination or decrease the band gap. TiO2 particles and the cationic−anionic layers surrounding
Wang and his colleagues19 produced Molybdenum and them. (ii) The TiO2 particles are prevented from sticking to one
Carbon doped TiO2, which benefits from the Carbon atom another by the electrostatic forces created by the double-layered
reducing the band gap and the Molybdenum atom reducing ILs (π−π stacking), which inhibit Van der Waals interactions
recombination, making it effective for the photocatalytic between the particles. (iii) The additional steric stability
oxidation of ammonia gas. The Ce/S TiO2 catalyst developed produced by the ILs’ alkyl side chains that stretch farther from
by Nasir et al.20 degraded the Acid Orange 7 due to its reduced the TiO2 surface prevents the TiO2 nanoparticles from
particle size, enhanced surface area, the surface increased approaching one another.49,50
hydroxyl groups, and decreased electron−hole pair recombina- Moreover, ILs can lessen the interactions between the solute
tion rate. Xiaoying et al.21 established that Nitrogen−
and the solvent, attributable to their stronger attractive qualities.
Vanadium−TiO2 increases the photocatalytic degradation of
Researchers are interested in employing ILs as a capping agent in
tetracycline by decreasing the bandgap and e−−hole recombi-
the synthesis; because of their ability to stabilize, they can yield
nation of TiO2. Kumar et al.22 fabricated Phosphorus (P)−
an end product that does not agglomerate.51−54 The most
Nickel (Ni)−TiO2, which offers improved separation of
significant research was done on an ionic liquid called 1-Butyl 3-
photogenerated electron−hole pairs and higher light absorption
in the visible range. Nasir et al.23 synthesized Cerium (Ce) and Methyl Imidazolium Tetrafluoroborate [BMIM BF4] (Figure
Nitrogen (N) doped TiO2 for the decolorization of Acid Orange S17(b)), which effectively resists agglomeration and provides
7, where a Ce/N doped catalyst increases electron−hole pair the doped TiO2 its unique size and form.55,56 Hence, the current
separation and reduces the band edge. Research indicates that work focuses on doping of Cerium (Ce) and phosphorus (P)
metal and nonmetal doping into the TiO2 lattice is a promising into the TiO2 framework concurrently, using an ionic liquid-
approach to overcome these limitations to improve photo- assisted modified sol−gel method. This study examines the
catalysis. effects of IL [BMIM BF4] on Cerium and Phosphorus doping,
Cerium ion (Ce4+/Ce3+) is an ideal dopant for modifying the dispersion, and size control of TiO2 particles using a modified
TiO2 lattice and electronic structure, adjusting optical sol−gel process.
absorption properties, and increasing quantum efficiency.24 The photocatalytic effectiveness of Cerium and Phosphorus
Reli et al.25 synthesized novel Ce-doped TiO2, which enhances doped TiO2 was evaluated by measuring the degradation rate of
the decomposition of ammonia by increasing electron−hole Alizarin Red S (ARS) under visible light. Organic dyes are
separation. Lee et al.,26 Silva et al.,27 Fan et al.,28 and Jafari et al.29 biodegradable, toxic, carcinogenic, and recalcitrant and are
synthesized Ce-doped TiO2 to enhance photocatalytic activity visible at extremely low concentrations of less than 1 ppm.
by reducing the recombination rate of electrons and holes. Dutta Alizarin Red S (C14H7NaO7S·H2O) (Figure.S17(a)) is a
et al.30 found that Ce-TiO2 fine powder has a higher oxygen carcinogenic and hazardous water-soluble anthraquinonoid
storage capacity than either CeO2 or TiO2, based on dye commonly used to color cotton, wool, and nylon textiles.
experimental and density functional theoretical analysis. It is a persistent contaminant in aquatic ecosystems.57,58
Shayegan et al.31 produced surface-fluorinated Ce-doped TiO2 In addition to the degradation process, the antibacterial
particles to remove volatile organic contaminants by reducing activity was assessed against Enterobacter aerogenes (MTCC-241,
electron−hole recombination. Gram-negative bacterium), Salmonella typhimurium (MTCC-
Phosphorus doping in the TiO2 lattice has gained significant 98, Gram-negative bacterium), and Candida albicans (MTCC-
attention due to its ability to incorporate phosphorus directly 277, fungi). Enterobacter aerogenes, found in the gastrointestinal
into the TiO2 framework by overlapping Phosphorus and system, can cause skin and eye infections, meningitis,
Oxygen orbitals. This creates an additional energy band that bacteremia, pneumonia, and urinary tract infections. Salmonella
decreases TiO2’s bandgap,32−35 prevents the formation of grains typhimurium is a common cause of gastroenteritis in humans,
with large surface area particles,36 and stabilizes TiO2’s leading to fever, diarrhea, and stomach cramps. Candida
mesoporous structure.37 According to Mohamed et al.,38 the albicans, present in trace amounts on the lips, skin, and
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intestines, can cause thrush and vaginal yeast infections when was then resynthesized in beakers 1, 2, 3, and 4 until sol
there is an imbalance with beneficial microorganisms.59,60 formation. Subsequently, each beaker was filled with varying
A novel ionic liquid-mediated sol−gel method was proposed weight percentages (3, 5, 10, and 15 wt %) of the capping agent
for fabricating Ce and P doped nanomaterials. The reduction in Ionic Liquid (1-Butyl-3-methylimidazolium tetra fluoroborate
the band gap and electron−hole recombination of the catalysts [BMIM BF4]). The mixture was stirred for 15 min and then kept
was confirmed through measurements of flat band potentials in the beaker in the dark for 48 h of aging to produce a gel. For 24
using VBXPS, EIS, and TCSPC, respectively. During the h, the gel was dried in an oven at 75 °C, and the resultant crystals
photocatalytic process, the catalyst’s surface charge was were ground for 4−6 h to obtain a fine powder. The fine powder
determined via zeta potential analysis. To evaluate the was then calcined in a muffle furnace for 5 h at 450 °C. The
photostability of the catalyst, a recycling process was performed. powder was collected, finely ground, and then put into amber
colored vials. Table 1 lists these catalysts with the codes
2. EXPERIMENTATION CPT5IL1, CPT5IL2, CPT5IL3, and CPT5IL4. Using the
previously mentioned method, Pristine TiO2 was produced
2.1. Materials for Experimentation. Tetra-n-Butyl Ortho free of dopants and IL.
Titanate (Ti(OBu)4) (98%) (E-Merck, Germany), Cerium 2.3. Characterization. Utilizing an Ultima IV Rigaku (40
Nitrate (Ce(NO3)3·6H2O) (E-Merck, Germany), and Triethyl kV/30 mA) apparatus, all PXRD data was acquired. The angle
Phosphate ((C2H5)3PO4) (High Media, India) were the starting range 2θ was 10°− 80°, and the Cu Kα radiation was scanned at a
precursor materials for Titanium(IV), Cerium (Ce3+), and rate of 0.02° per min. The average crystallite sizes of all the
Phosphorus (P5+) utilized for the fabrication of Cerium and codoped TiO2 and the Pristine TiO2 samples were determined
Phosphorus doped TiO2. The scissoring agent utilized in the by using Debye−Scherrer’s equation and are shown in Table 2.
fabrication to produce the nanomaterial is ionic liquid 1-Butyl-3-
methylimidazolium tetra fluoroborate [BMIM BF4] (E-Merck, k
D=
Germany). C2H5OH and HNO3, the solvents employed in the cos (1)
experiment, were purchased from Hayman (UK) and Merck A Shimadzu 3600 UV−visible DRS NIR spectrophotometer
(Germany), respectively. Throughout the procedure, milli-Q was used to evaluate the 200−800 nm absorption edges of the
water was utilized. synthesized samples. The results were compared to those of a
2.2. Fabrication of Cerium and Phosphorus Doped BaSO4 reference and background measurement. A 5 nm spectral
TiO2 Catalysts. In a 150 mL Pyrex glass beaker, Solution-1 was bandwidth and a 1.0 nm resolution were used to cover the 200−
prepared by mixing 40 mL of C2H5OH with 20 mL of tetra-n- 800 nm measurement range. The microstructure and chemical
butyl ortho titanate, followed by stirring for 10 min. composition of synthesized TiO2 samples were characterized
Subsequently, 3.2 mL of HNO3 was gradually added, and using high-resolution transmission electron microscopy
stirring was continued for an additional 30 min. In a separate 150 (HRTEM) combined with energy-dispersive X-ray spectrosco-
mL Pyrex beaker, the required amounts of Ce(NO3)3 and py (EDX) on an FEI Tecnai G2 system equipped with a
(C2H5)3PO4 dopants were dissolved in 40 mL of C2H5OH and Schottky field emission electron gun, operated at 200 kV.
7.2 mL of H2O to prepare Solution-2, which was then stirred for X-ray photoelectron spectroscopy (XPS) was used to
30 min. Solution-2 was added dropwise to Solution-1 using a ascertain the catalyst’s chemical states and elemental makeup.
buret, and the combined solution was stirred for 30 min until sol The catalyst’s elemental spectra were recorded and magnified
formation occurred. The resulting sol was aged in the dark for 48 using an Al Kα 250 W X-ray emitter, which had 1486.6 eV of
h and then subjected to a drying process at 75 °C for 24 h to irradiation power, 16 mA of current, and 12.5 kV of voltage. The
obtain a gel. The formed crystals were subsequently crushed into Valency band XPS was analyzed by Reflected Electron Energy
a fine powder over 4 to 6 h. Loss Spectroscopy (REELS). Using a scanning electron
The finely ground material was then calcined in a muffle microscope equipped with an energy dispersive X-ray
furnace for 5 h at 450 °C. The fine powder was collected, spectrophotometer (Model PHI quantum ESCA microprobe
ground, and then put into amber vials for packaging. The names model) running at 20 kV, we examined the morphology and
of the catalysts, CPT1, CPT2, CPT3, CPT4, and CPT5, are elemental content of the doped catalysts. Following a 4 h
assigned and listed in Table 1. Out of all the catalysts, CPT5 degasification process at 250 °C, the N2 adsorption−desorption
performs the best based on degradation of Alizarin Red S using isotherm at −196 °C was utilized to calculate the pore volume
the catalysts discussed in section 4. The chosen catalyst, CPT5, and surface area (SBET). Utilizing a Brunauer−Emmett−Teller
(BET) surface area analyzer (Model: Micrometrics of the
Table 1. Assign the Names to Synthesized Catalysts Gemini VII 2390), this was accomplished. For the photo-
luminescence spectral analysis, the Horiba Jobin Fluoro Max-4
Cerium Phosphorus BMIM BF4 was used in conjunction with a 2.5 nm slit and a 150 V PMT, and
wt.% wt.% wt.% Label
samples are excited at 300 nm.
1 0.25 1.00 0.00 CPT1 Electrochemical experiments were performed using an
2 0.25 0.75 0.00 CPT2 electrolyte solution consisting of 2 mM K3[Fe(CN)6] and 0.1
3 0.50 0.50 0.00 CPT3 M KCl in a typical three-electrode system consisting of a
4 0.75 0.25 0.00 CPT4 platinum functioning electrode, a platinum wire as the counter
5 1.00 0.25 0.00 CPT5 electrode, and a saturated silver and silver chloride reference
6 1.00 0.25 3.00 CPT5IL1 electrode. A thin layer of photocatalyst was spin coated on the
7 1.00 0.25 5.00 CPT5IL2 platinum working electrode for the EIS measurements. Using a
8 1.00 0.25 10.00 CPT5IL3 CHI 606E electrochemical analyzer (CHI Inc., USA), the
9 1.00 0.25 15.00 CPT5IL4 electrochemical response was recorded. Furthermore, model
10 0.00 0.00 0.00 PT (Pristine TiO2) XGT 5200, based in Horiba, Japan, was used to assess the
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Table 2. Lattice Constants (a and c), Unit Cell Volume, Average Crystallite Size, and Band Gaps of the Ce and P Doped TiO2
Nanoparticles
Lattice parameters (Å)
Sample a c c/a Cell volume (Å3) Average crystallite size (nm) Band gap (eV)
PT 3.7877 9.5004 2.5082 136.3005 12.1 3.12
CPT1 3.7901 9.5006 2.5067 136.4767 8.1 2.97
CPT2 3.7916 9.5021 2.5061 136.6045 7.8 2.95
CPT3 3.7921 9.5029 2.5060 136.6524 7.5 2.90
CPT4 3.7912 9.5048 2.5071 136.6150 7.3 2.88
CPT5 3.7908 9.5082 2.5082 136.6343 6.5 2.75
CPT5IL1 3.7908 9.5062 2.5077 136.6057 6.2 2.67
CPT5IL2 3.7911 9.5091 2.5083 136.6690 4.5 2.59
CPT5IL3 3.7917 9.5073 2.5074 136.6863 6.4 2.73
CPT5IL4 3.7922 9.5088 2.5075 136.7440 7.7 2.85

elemental composition using X-ray fluorescence (XRF). Ao is a representation of the initial dye absorption before light
Analyzed using a Bruker, Germany, model 3000 Hyperion exposure. At denotes the absorbance at time t after exposure to
Microscope with a Vertex 80 spectrometer, the synthesized light. The best codoped catalyst for degrading Alizarin Red S,
doped samples performed Fourier transform infrared (FTIR) among the synthesized catalysts, was found. By varying the pH
spectroscopy in transmission mode using the KBr pellet method. values (pH = 2, 3, 5, and 6) with this best degradation catalyst,
Alizarin Red S dye photocatalytic degradation was studied using the ideal pH conditions were investigated. By maintaining the
a UV−visible spectrophotometer (Model: Shimadzu 1601), best pH conditions, varying the catalyst dose (0.05, 0.10, 0.15,
with a Horiba scientific SZ-100 nanoparticle analyzer with a gold 0.20, and 0.25 g) identified the best catalyst dose. Then, while
coated cuvette (6 mm) used for the zeta potential measurement maintaining the other ideal circumstances constant, the best dye
at 25 °C at different pH values. A digitally displayed Elico pH dose was investigated with variations in dye concentration (5,
meter (design: IIIE, emotional intelligence) was utilized to 10, 15, 20, and 25 mg/mL). In section 4, the optimal
continuously monitor the pH while the dye degraded in the circumstances were described. The active species in the
reaction mixture. catalyst-assisted photocatalytic process were identified by
2.4. Procedure for Assessment of Photocatalytic using scavenger testing. As a scavenger agent for electron/hole
Activity of Ce and P Doped TiO2 by Degradation of detection, EDTA was used to slow down the degradation
Dye and Microbes. a). Alizarin Red S Mineralization. The process by trapping the electron/hole. Similarly, 1,4-benzoqui-
potential of the prepared CPT nanocatalysts was measured by none was added as a scavenger for superoxide radical detection,
using the mineralization of Alizarin Red S (ARS) under visible demonstrating a decreased degradation as a result of radical
light irradiation in order to assess their photocatalytic efficacy. scavenging. The existence of hydroxyl radicals was confirmed by
To achieve the optimized conditions for complete mineraliza- adding coumarin and utilizing photoluminescence at 450 nm to
tion of Alizarin Red S dye, experiments were conducted using trace the production of 7-hydroxycoumarin. All these experi-
400 W of a high-pressure mercury halide bulb from Osram, ments are discussed in section 4.
India, with an intensity of 35,000 Lm serving as the visible b). Antimicrobial Activity. Although TiO2 is a powerful
radiation source. An Oriel no. 5172 UV filter was used to remove antimicrobial agent, its efficacy varies with the particle size and
UV radiation, with the visible light irradiation source’s output phase. Due to their large surface area, small nanoparticles
436−646 nm. possess antimicrobial properties. Using the agar-well diffusion
In the absence of light, the required quantity of catalyst and method, microbicide tests were conducted on a high surface area
the required pH were attained by adding 0.1 M HCl or 0.1 M synthesized sample called CPT5IL2, targeting three distinct
NaOH (acidic or basic) in a 150 mL Pyrex glass beaker and microbes: Enterobacter aerogenes (MTCC-241, Gram-negative
stirring for 10 min, and then 100 mL of the required dye solution bacteria), Salmonella typhimurium (MTCC-98, Gram-negative
(5, 10, 15, and 20 mg in 1000 mL) was added and kept in the bacteria), and Candida albicans (MTCC-797, fungi). This
dark with stirring for 60 min to establish the equilibrium method employed nutrient-agar and potato dextrose agar as its
between the catalyst and dye solution, after which the mixture media for its antibacterial and antifungal properties, which were
was taken out of the reaction vessel and exposed to visible autoclaved for 20 min at 121 °C and 15 pounds of pressure.
radiation by maintaining a 20 cm distance between light source Before addition of the agar medium, the Petri dishes were
and reaction beaker. Cool water was circulated around the sanitized and left to set in a sterile environment to solidify. A
reaction vessel to maintain room temperature and to filter the IR clean and solidified Petri dish was used to equally distribute the
radiation. Using a Millipore syringe, 5 mL of the reaction bacterial and fungal strains’ medium broth cultures, which were
mixture was withdrawn from the reaction vessel at regular dispersed using an L-shaped glass rod. Each Petri dish has four
intervals. A UV−visible absorption spectrometer was used to bore wells made with a sterile cork borer that had a diameter of 6
evaluate the dye absorbance at λmax = 530 nm. The degradation mm. In one of the four bore wells, Petri dishes were filled with
three different concentrations of the CPT5IL2 sample (400,
percentage for each of the synthesized photocatalysts was
600, and 800 μg/mL) and one concentration of the standard (50
determined using eq 2 under the same conditions.
μg/mL). Following a 10 min period of visible light activation,
(A o A t ) × 100 the bacterial Petri dishes were placed in an incubator at 37 °C for
Degradation % = a period of 24 h. Over the course of 2 days, the fungal Petri dishes
Ao (2) were incubated at 37 °C. To determine how effective CPT5IL2
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Figure 1. (a) PXRD of CPT1 to CPT5 catalysts and (b) PXRD of CPT5IL1 to 4 catalysts and Rietveld refinement of XRD pattern of catalysts (c) PT
and (d) CPT5IL2.

nanoparticles were as antimicrobials, the inhibitory zone was The four catalysts’ PXRD patterns are shown in Figure 1(b).
utilized with reference to standards. The millimeter antibiotic Using the same formula, the crystallite sizes of all the catalysts
scale was used to quantify the sample’s inhibition zone. were determined. CPT5IL2 has the smallest crystallite size,
measuring 4.5 nm. The Rietveld refinement of the XRD pattern
3. RESULTS AND DISCUSSION of PT and CPT5IL2 is shown in Figure 1(c) and (d). According
to Table 2’s unit cell parameters, there was no discernible change
3.1. Powder X-ray Diffraction for Structural Analysis. in the phase “a” lattice parameter for any of the samples
In order to ascertain the size, cell characteristics, and purity of containing Ce and P. Nonetheless, small distortion was detected
the samples as well as to determine the anatase phase followed at on the “c” lattice parameter, indicating that the incorporation of
450 °C calcination temperature, the PXRD patterns of pristine Ce had caused stress in the structure; this contributed to the
TiO2 and all doped samples are displayed in Figure 1(a). The decrease in particle size. These results are also in agreement with
interpretation of the PXRD patterns of all the samples indicated those of Hao et al.67 and Nasir et al.23
that the formation of anatase phase (CPT1, CPT2, CPT3, 3.2. UV−Visible DRS. Figure S2 presents the findings of the
CPT4, and CPT5) at 2θ is 25.4° (1 0 1), 37.9° (0 0 4), 48.0° (2 0 UV−Vis DRS optical absorption studies that were carried out
0), 54.5° (2 1 1), 62.6° (2 0 4), and 75.2° (2 1 5) (JCPDS # 21- for the Ce and P doped TiO2 samples. Pure TiO2 is significant at
1272). The lack of other peaks in Figures 1 and S1(a) for rutile, the 380 nm absorption edge. This absorption maximum was
brookite, CeO 2 (at ∼28.7°), Ce 2O 3 (at ∼28.5°), and changed from 420 to 490 nm, a higher wavelength (red-shifted),
phosphorus oxides implies that Ce and P61,62 were introduced in the visible range for all of the Ce and P doped materials. The
into the TiO2 framework. shift could result from one of the following: (i) P doping, which
In contrast to Pristine TiO2, Table 2 indicates that the CPT5 creates additional energy bands just above the valency band by
sample has a smaller crystallite size of 6.5 nm out of all of the overlapping the 2p orbitals of Phosphorus and Oxygen. (ii) The
samples. This may be confirmed by the broadening of peaks and 3d orbitals of cerium and the Ti 3d orbitals of TiO2 overlap,
decrease in intensity by the increase in Ce concentration from producing an extra band below the conduction band. The
CPT1 to CPT5.63 As the Ce concentration increases, evidence for the decrease in band gap and electron hole
segregating grain boundaries increase.64−66 As discussed in recombination is discussed in preceding sections. Thus, it can be
Section 4, all of the codoped samples exhibited photocatalytic deduced that the enhanced optical absorption in the codoped
degradation of Alizarin Red S, with CPT5 demonstrating the CPT nanoparticles, which in turn results in better photocatalytic
highest photocatalytic efficiency. To further reduce the particle activity by lowering band gap and separation of electron−hole
size and increase the surface area of CPT5, the ionic liquid pairs, is caused by the synergetic action of both Ce and P. By
[BMIM BF4] was used as a capping agent, enhancing the using the Kubelka−Munk approach, Tauc plots were drawn to
photocatalytic rate. Section 2.2 describes the steps involved in determine the bandgap energy in eV. The resulting Tauc plots
synthesizing CPT5IL1, CPT5IL2, CPT5IL3, and CPT5IL4. are depicted in Figure 2(a) and 2(b), respectively. For each of
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Figure 2. [F(R)hν)1/2] vs the photon energy (hν) for PT, CPT1 to CPT5 (a), and CPT5IL1 to CPT5IL4 (b).

Figure 3. XPS valence band spectra of CPT5 and CPT5IL2 (a), VBXPS of PT (b), VBXPS of CPT5 (c), and VBXPS of CPT5IL2. (d) Schematic
diagram of the DOS of PT, CPT5, and CPT5IL2 (e).

the samples, the bandgap energies are displayed in Table 2, and maximum energy at around 2.51 eV (Figure 3(b)), while
the band gap energy was ascertained by extending the linear CPT5’s valence band maximum energy was calculated to be 2.31
segment of the graphs intersecting the X-axis. The table shows eV, followed by a band tail at about 1.72 eV (Figure 3(c)). The
that at 2.59 eV, CPT5IL2 has the lowest band gap energy. predicted maximal energy of CPT5IL2’s valence band was 2.03
3.3. Valency Band XPS. In order to gain a deeper eV, with a band tail at around 1.38 eV (Figure 3(d)). The
comprehension of the band gap narrowing process in doped Prisitne-TiO2, CPT5, and CPT5IL2 have optical band gap
materials, a valence band XPS analysis was conducted and is energies of 3.12, 2.75, and 2.59 eV, respectively. Consequently,
shown in Figure S3. The resulting densities of electronic states approximately −0.62 eV, −0.44 eV, and −0.55 eV, respectively,
for pristine TiO2, CPT5, and CPT5IL2 were also obtained. The would be the conduction band (CB) minima of Prisitne-TiO2,
VBXPS spectra of both CPT5 and CPT5IL2 are shown in Figure CPT5, and CPT5IL2. TiO2 has valence band maxima and
3(a). The VB width of CPT5IL2 (6.35 eV) is greater than those conduction band minima that contribute to its band gap
of CPT5 (6.17 eV) and Pristine anatase TiO2 (6.05 eV) (Figure reduction. The displacement of Cerium and Phosphorus in the
S3),68 indicating a comparatively better charge movement TiO2 lattice system may be the cause of the study’s decrease in
capacity in the Ce and P doped TiO2. As compared to CPT5, band gap.
CPT5IL2 has a better charge mobility. For Pristine TiO2, the 3.4. Photoluminescence Spectroscopy. Photolumines-
valence band DOS characteristics exhibited an edge of cence spectra (PLS) have been exploited extensively in
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Figure 4. (a) PL spectra of as synthesized samples by using 300 nm wavelength for excitation and (b) TCSPC analysis excited at 300 nm and emission
at 395 nm.

Figure 5. (a) Nyquist plot of impedance from 100 MHz to 100 mHz, inset shows corresponding equivalent circuit. (b) Mott−Schottky plots for PT,
CPT5 and CPT5IL2 samples.

semiconductors to investigate the electron−hole pairs’ destiny conduction energy band moves to the additional new energy
by assessing the effectiveness of charge carrier movement, bands, and transferring the electron to oxygen molecules which
transfer, and trapping. In particular, longer photogenerated are adsorbed on the surface of the catalyst. Consequently, Ce3+
carrier life spans and slower recombination rates are indicated by and Ce4+ are present. Similar in PL intensity to that of the CPTs
lower photoluminescence intensity.69,70 The PL spectra of the as sample, the CPT5IL samples also reduced electron−hole
synthesized samples are illustrated in Figure 4(a) and show that recombination. The rate of dye degradation or photocatalysis
all the photocatalysts have almost equal PL spectra with the therefore rises. As per the reference cited,75−77 the electron
exception of peak intensity and peak positions. The broad movement between valency bands and conduction bands is
emission peak between 380 to 400 nm in the spectrum explains tracked using fluorescence lifetime spectra or time correlated
the recombination of the photoexcited electron transition from single photon counting (TCSPC). The PT and CPT5IL2
the conduction band to the valency band.71,72 The emission lifetime spectra are displayed in Figure 4(b) at an excitation
peaks at 437 nm, 448 nm and 466 nm are attributed to the wavelength of 300 nm and an emission wavelength of 395 nm. In
shallow trap states near the absorption band emission which are comparison to PT, CPT5IL2 exhibits a longer life span
due to oxygen defects and impurity defects.73 And the emission measured in nanoseconds.
peaks at 482 nm and 491 nm correspond to the deep trap 3.5. Electrochemical Impedance Spectroscopy (EIS).
states.74 Nanostructures’ utility in fields such as catalysis is dependent on
Pristine TiO2 exhibits the maximum intensity in Figure 4(a), their accessibility and capacity to conduct charges across
indicating the lack of elctron−hole separation. The intensity interfaces with other materials. An efficient method for studying
drastically drops from CPT1 to CPT5, indicating the separation materials’ frequency-dependent transport characteristics is
of electron−hole is high as the Ce weight percentage increases in electrochemical impedance spectroscopy (EIS). The results
the catalyst. This is a result of Ce doping, which creates an are shown in Figure 5(a) as a Nyquist plot with a 50 mV bias
additional energy band by acting as an electron trapper beneath potential, covering a frequency from 1 MHz to 0.1 Hz using an
the conduction band. Because of the electron transfer redox electrolyte solution of 2 mM K3[Fe(CN)6] and 0.1 M KCl. The
coupling of Ce3+ and Ce4+, the photoexcited electron in the real and imaginary components of complex impedance are
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Figure 6. SEM images of (a) PT, (b) CPT5, (c) CPT5IL2. HRTEM images of (d) PT, (e) CPT5, (f) CPT5IL2. (g) Lattice fringes of PT and (h)
CPT5IL2 and (i) SAED of CPT5IL2.

represented by ZReal and ZImg, respectively, and the measured type.83 The potential that is supplied to flatten out the band
spectra are fitted with EIS software. The resulting equivalent bending at the semiconductor/electrolyte boundary is known as
circuit consists of resistance (R), constant phase elements (Q), the flat-band potential (Efb).84 The Efb values are −0.05 V, −0.19
and a Warburg impedance component (W). The equivalent V and −0.30 V for the samples Prisitne TiO2, CPT5, and
circuit is similar to Randles’ circuit and gives rise to RS (total CPT5IL2 vs Ag/AgCl.
internal resistance) and the parallel connection of RCT and Q, 3.6. SEM-EDX and Transmission Electron Microscopy
which shows the small arc in the high frequency region that (TEM). Figure 6(a), (b) and (c) indicate that the scanning
comes from the interface between the counter electrode and the electron micrographs (SEM) of pristine TiO2, CPT5, and
electrolyte. The Q comes from the interface between the CPT5IL2 calcined at 450 °C. It may be seen from Figures 6(b),
working electrode and the electrolyte at low frequencies. It is 6(c), S4, S5 and S6 that the morphology remains unchanged in
connected parallel to the RCT at low frequencies and the both the absence and presence of ionic liquid for the best
Warburg element (W) as a result of the movement of ions at the codoped sample (CPT5). There is no change in the morphology
interface between the working electrode and the electro- even with varying concentrations of ionic liquid. Agglomeration
lyte.78−80 The charge transfer process plays a key role in of particles of pristine TiO2 has been revealed. In CPT5 and
reaction rate and kinetics.81 Resistance at the low frequency CPT5IL2, the particle size distribution is smaller, and the
region decreases as the PT (10890 Ω) moves to CPT5IL2 (1019 dispersion of particles is more homogeneous. The element
Ω). This could be explained by the Ce element, which has the content of TiO2, CPT5, and CPT5IL2, which had been calcined
ability to generate an energy band just below the conduction at 450 °C, was investigated using EDX testing. The findings are
band, facilitating an easier electron transfer. And also the shown in Figure S7. The components Ti and O have distinct
phosphorus atom forms a band just above the valency band to peaks in the Pristine TiO2 spectrum. The presence of Ce and P
facilitate the charge transfer. elements in codoped TiO2 nanomaterials is confirmed by the
To examine the impact of Ce and P doping in TiO2 in more CPT5, CPT5IL2 spectrum, which also exhibits peaks for Ti and
detail, their electrochemical impedance is determined at a fixed O elements.
frequency (1 kHz) against applied voltage from 3 V to −0.5 V The as-obtained pristine TiO2 is comprised of irregularly sized
using an electrolyte solution of 2 mM K3[Fe(CN)6] and 0.1 M nanoparticles with an average size of around 12.5 nm, as
KCl. Using the Mott−Schottky equation,82 the space-charge illustrated in Figure 6(d). As synthesized sample CPT5 consists
capacitance (Csc) at the semiconductor electrode/electrolyte of small particles as compared to PT with a diameter of 9.6 nm
interface is estimated using the impedance data. The variation of (Figure 6(e)). As compared to both CPT5 and PT, CPT5IL2
1/Csc2 as a result of potential for the samples PT, CPT5, and (Figure 6(f)) has an average particle size of 6.2 nm, which may
CTP5IL2 is displayed in Figure 5(b), and positive slopes are be due to the capping effect of the ionic liquid, which prevents
seen in the M-S plots, which suggests that the samples are n- particle aggregation. Among the Ionic Liquid assisted
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Figure 7. Adsorption-Desorption of (a) PT, (b) CPT5, (c) CPT5IL2. BET surface area of (d) PT, (e) CPT5, (f) CPT5IL2. BJH plots of (g) PT, (h)
CPT5, and (i) CPT5IL2.

synthesized CPT5 samples, the CPT5IL2 has the smaller isotherms and a Braunauer−Emmett−Teller (BET) surface area
particle size, and the CPT5IL1, CPT5IL3, and CPT5IL4 analyzer. According to the IUPAC classifications, type-IV
average particle sizes are 8.3 nm (Figure S4), 9.2 nm (Figure S5), isotherms have been identified by Pristine TiO2, CPT5, and
and 10.2 nm (Figure S6), respectively. At below or above the 5 CPT5IL2, and H4 type hysteresis loops were observed, as shown
wt % IL concentration, the capping efficiency decreases. This in Figure 7(a), (b), and (c). This represents that all the
may be attributed to the fact that at low concentration it is not synthesized samples are mesoporous. The amount of catalyst’s
enough to act as a capping agent and at high concentration the N2 adsorption and desorption isotherms increases, as we move
reaction system’s viscosity rises, which leads to uneven reactant from Pristine TiO2 to CPT5IL2.
dispersion in the entire solution and particle aggregation. CPT5IL2 can therefore offer progressively active places for
Figures 6(g) and 6(h) show lattice fringes indicating high surface reactions because, as shown in Figure 7(d), (e), and (f),
crystallinity in PT and CPT5IL2, with fringe spacings of 0.3503 its BET results show a greater apparent surface area (166 m2/g)
and 0.357 nm, respectively, corresponding to the (101) plane of than those of CPT5 (115 m2/g) and PrisitneTiO2 (83 m2/g).
anatase TiO2. Figure 6(i) shows different planes of CPT5IL2 The large surface area of the catalysts can promote the pollution
with concentric rings, confirming extensive crystallinity, abatement rate.85 In addition to those previously described, the
consistent with XRD patterns. Berret−Johner−Halenda (BJH) plots shown in Figure 7(g),
3.7. Braunauer−Emmett−Teller (BET) Analysis. Pristine (h), and (i) were used to investigate the variation in pore sizes
TiO2, CPT5, and CPT5IL2 catalysts’ surface areas and porous and pore volumes of the three synthesized materials (Pristine
structures were investigated utilizing N2 adsorption−desorption TiO2, CPT5, and CPT5IL2). The BJH plot is useful for
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Figure 8. PT, CPT5, CPT5IL2 of (a) survey spectrum, (b) Ti 2p, (c) Ce 3d of CPT5, CPT5IL2 (d), P 2p of CPT5, CPT5IL2, and (e) O 2p of PT,
CPT5, CPT5IL2.

observing the connectivity, diversity, and size distribution of The magnified spectra of Ce 3d in Figures 8(c) and S9 are
pores. The graph indicates that the Pristine TiO2, CPT5, and complex due to the various oxidation states and hybridization of
CPT5IL2 samples have a majority of the pore diameters as 1.22 the O 2p and Ce 4f orbitals, causing peak doublets during
1.66, and 3.15 nm, respectively. primary photoemission.90 The spectrum features two spin−
3.8. XPS. The XPS study results validated the oxidation states orbital states, Ce 3d5/2 (“v”) and Ce 3d3/2 (“u”). Ce 3d5/2 has five
and composition of all samples, with pristine TiO2, CPT5, and peaks: vo, v, v′, v″, and v‴. Peaks v and v′′ represent the mixed
CPT5IL2 findings shown in Figure 8 and other samples in the electronic configurations 3d9 4f2 (O 2p4) and 3d9 4f1 (O 2p5) of
Supporting Information. Strong Ti and O peaks in Figure 8 Ce4+, attributed to bonding and antibonding states, while v‴
indicate the high purity of the mesoporous TiO2-based corresponds to the 3d9 4f0 (O 2p6) configuration of Ce4+. Peaks
photocatalysts. High-resolution spectra in Figure 8(c) and vo and v′ are due to the 3d9 4f2 (O 2p5) and 3d9 4f1 (O 2p6)
8(d) reveal distinctive Ce and P peaks, confirming the doping of configurations of Ce3+. Similar configurations apply to the “u″
Ce and P into the TiO2 structure, as supported by shifts in the Ti term of Ce 3d3/2.27 The Ce 3d spectra of the CPT5 and
2p and O 1s peak positions. The C 1s peak indicates adventitious CPT5IL2 catalysts show multiple Ce3+/4+ oxidation states,
carbon. indicating some oxygen vacancies and incomplete oxidation.
The high-resolution XPS spectrum of Ti 2p is shown in Peaks at 885.7 and 903.8 eV are associated with Ce3+, while
Figures 8 (b) and S8. Two peaks at around 458.6 eV (Ti 2p3/2) peaks at 882.6 and 901.2 eV correspond to Ce4+.
and 464.4 eV (Ti 2p1/2) were observed for all CPT and CPT5IL In Figures 8(d) and S10 the high-resolution spectra of
catalysts. Pristine TiO2 shows Ti 2p3/2 and Ti 2p1/2 peaks at phosphorus show a distinctive signal at 133.1 eV, corresponding
458.3 and 464.0 eV, respectively, confirming the presence of Ti4+ to P 2p (P5+).37 P5+ can replace Ti4+ in the crystal lattice due to
with a 5.81 eV gap between them. For CPT5IL2 and CPT5, Ti their ionic radii of 0.35 and 0.68 Å, respectively. This
2p3/2 and Ti 2p1/2 peaks are at 458.74 and 458.72 eV and 464.43 substitution creates a charge imbalance, leading to the formation
and 464.36 eV, respectively. Comparing these CPT and CPT5IL of Ti−O−P bonds, which may enhance the separation of
catalysts (Figure S8) with pristine TiO2, a slight shift of photogenerated electron−hole pairs.32
approximately 0.3 eV is observed, indicating a strong interaction In Figures 8(e) and S11, the high-resolution (HR) spectra of
among Ti, P, and Ce species.86 Wang et al.87 reported 0.29 eV O 1s for PT, CPT5, CPT5IL2, and all samples are presented. For
shifting in Ti 2p3/2 for 1.0% Ce-TiO2. This shift suggests changes all codoped samples, the peak at 529.72−530.11 eV corresponds
in Ti oxidation states (from Ti4+ to Ti3+), indicating Ce to lattice oxygen O2− (Oβ), and the peak at 531.13−531.35 eV
incorporation into the TiO2 lattice, increasing Ti3+ and creating corresponds to surface hydroxyl oxygen (Oα).89 PT shows peaks
oxygen vacancies.88 Deng et al.89 also noted that Ce affects Ti at 529.58 and 530.81 eV, attributed to surface hydroxyl groups
oxidation states and oxygen vacancy formation, confirming (OH−) and crystal oxygen (O2−).91,92 The shifts in O 1s and Ti
successful Ce and P doping into TiO2. 2p peaks are due to electron transfer from O 1s and Ti 2p orbitals
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to Ce 4f orbitals, changing the charge densities of O and Ti method that involves irradiating it with high-energy X-ray
atoms.93 The composition of the as prepared catalysts CPT5IL2, radiation and monitoring the fluorescence. This approach can be
CPT5 and PT using XPS analysis and results that are shown in used to precisely identify atomic numbers ranging from 11(Na)
Table 3 indicate that the composition of the catalysts and the to 92(U). Figures 9(b), (c), and (d) display the XRF spectra for
CPT5IL2 and its chemical composition.
Table 3. XPS Compositions of PT, CPT5 and CPT5IL2
Element (Atomic %) 4. PHOTOCATALYSIS OF THE CATALYSTS
S.No Photocatalyst Ti O Ce P C Prior to determining the optimum reaction conditions, experi-
1 PT 25.2 53.2 - - 21.5
ments were conducted to evaluate the catalyst and light’s
2 CPT5 24.2 54.2 0.9 0.2 20.5
dependability.
3 CPT5IL2 25.0 55.7 0.9 0.2 18.2
4.1. Preliminary Tests. Initially, 100 mL of agitated 5 mg/L
dye solution was placed in a 150 mL Pyrex glass beaker and
exposed to light. Periodically, 5 mL aliquots were withdrawn,
concentrations of the dopants that were present in the catalyst and the dye’s characterized absorbance at λmax 530 and 430 nm
were very close to the actual doped concentration in the lattice. was determined. There was no apparent shift in the Alizarin Red
3.9. FTIR and XRF Analysis. The FTIR spectra of Pristine S dye’s absorption.
TiO2, CPT5, and CPT5IL2 are displayed in Figure 9(a), with The aforementioned solution was then taken and maintained
the remaining samples shown in Figure S12. Pristine TiO2 at an acidic or basic pH. Next, 0.05 g of catalyst was added, and it
exhibits a Ti−O−Ti stretching frequency at 507 cm−1,94 while was agitated for 60 min in the dark. This procedure was used to
CPT5 and CPT5IL2 show this frequency around 540 cm−1, periodically evaluate the absorbance at λmax 530 and 430 nm.
indicating Ce and P substitutional doping in Anatase TiO2. The There is a discernible drop in the dye solution’s absorbance. This
broadening of the Ti−O stretch is more pronounced in CPT5 took place because of Alizarin Red S dye molecules attaining an
and CPT5IL2 compared to that in Pristine TiO2 due to Ce−O− adsorption−desorption equilibrium on the catalyst surface.
Ti or Ce−O−Ti−O−Ce stretching frequencies. Additionally, a Following that, the previously described solution was taken
small absorption peak at around 1100 cm−1 in CPT5 and out of the dark and exposed to light, and exactly the same process
CPT5IL2, absent in Pristine TiO2, is attributed to Ti−O−P or was followed. The dye absorbance substantially decreased,
Ce−O−P bonds replacing some Ti4+ in the titania lattice. Peaks indicating that light is necessary for the activation of the catalyst
in the ranges of 3200−3600 cm−1 and 1620−1640 cm−1 to become active. Visible light is, therefore, the main element
correspond to O−H group stretching and adsorbed water that has the ability to activate the catalyst responsible for dye
molecule bending vibrations. A stretching frequency at 3750 degradation. This suggests a mutual dependence between the
cm−1, observed only in CPT5 and CPT5IL2, indicates Ce−OH light and the catalyst.
stretching frequencies.95 Determining both a material’s The above consequences are pictorially represented in Figure
quantitative and qualitative composition is a well-established 10(a). The photocatalytic capability was impacted by a variety of

Figure 9. (a) FTIR of PT, CPT5 and CPT5IL2. (b), (c) and (d) XRF analysis of CPT5IL2 catalyst.

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Figure 10. (a) Preliminary tests of degradation, CPT catalysts (b) ln(C/C0) vs time, (c) and catalysts vs k (rate constant), Degradation %.

Figure 11. CPT5IL catalysts (a) ln(C/C0) vs time (b) and catalysts vs k (rate constant), Degradation %.

factors, including dopant concentration, pH, catalyst dosage and of Ce and P into the TiO2 lattice, the band gap decreased to 2.75
Alizarin Red S concentration. It is thus essential to enhance the eV (evident by UV−vis DRS and VBXPS) and led to absorption
reaction rate to accomplish the appropriate reaction conditions. of more visible radiation per particle, which enhances the rate of
4.2. Efficiency Evaluation of the TiO2 Catalysts by degradation of dye. The rate of catalysis of catalyst increases due
Doping with Cerium and Phosphorus. A pH of 3 was to
maintained, 0.05 g of catalyst was used, and the starting Alizarin
Red S dye concentration was kept constant at 5 mg/L i) As the Ce concentration increases, grain strain increases,
throughout the experiments using various catalysts, including the particle size decreases, and surface area increases.
PT, CPT1, CPT2, CPT3, CPT4, and CPT5. The experimental
kinetic results are presented in Figures 10(b), (c) and S13. The ii) The catalyst’s large surface area attracts more dye
figures reveal that the CPT5 nanocatalyst shows the highest molecules, which accelerates the dye’s degradation
catalytic performance compared to others. Due to incorporation (Evident from the TEM, BET surface area study).

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Figure 12. CPT5IL2 catalyst (a) Zeta potential analysis, (b) ln(C/C0) vs time, and (c) pH vs k (rate constant) and Degradation %.

iii) Cerium cations’ greater electron scavenging ability, increase in the wt % of the Ionic Liquid [BMIMBF4] causes the
reducing the potential for electron (e−) and hole (h+) reaction system’s viscosity to rise, which leads to uneven reactant
recombination, could enhance photocatalytic activity. dispersion in the entire solution and particle aggregation.
The surface area plays a pivotal role by increasing the surface Further, the CPT5IL2 catalyst was used to study the other
area, which can provoke the synthesis of tiny nanoparticles. reaction parameters to optimize.
Hence, the present investigation synthesizes the nanoparticles of 4.3. pH Dependency on the Catalysis of CPT5IL2.
CPT5 by using ionic liquids [BMIM BF4] as a capping agent. According to earlier research,96 the pH of the solution has a
The synthesis process was discussed in the Experimentation significant impact on the catalyst’s modification charge, which
section 2. The synthesized CPT5IL1, CPT5IL2, CPT5IL3, affects how quickly dye degrades. At various pH levels, the
CPT5IL4 catalysts were taken to determine their catalytic ability catalyst’s surface charge was measured, and the findings are
by degradation of Alizarin Red S dye. As Figures 11 and S14 shown in Figure 12(a). From the figure, it is noticed that at pH
indicate that CPT5IL2 has the highest photocatalytic perform- 6.12 the catalyst attains zero-point charge. At pH below 6.12, the
ance for degradation of Alizarin Red S, it is implied that catalyst’s surface charge converted to a positive one, maybe as a
consequence of TiOH+2 formation.
i) There might be a hydrogen bond between the nitrogen of
the Imidazolium ring in the ionic liquid [BMIM BF4] and Ti OH(s) + H(+aq) Ti OH2+(s) (3)
the surface Ti−OH of the catalyst particle.
ii) The butyl side chains of ILs are long enough to restrict the At pH above 6.12, the catalyst’s surface charge converted to a
entry of more TiO2 particles to get agglomeration. negative one, maybe as a result of TiO− formation.
iii) Due to conjugation, the IL can be organized on the other Ti OH(s) + OH(aq) Ti O(s) + H 2O(aq)
side and further form π−π stacking, causing encapsulation (4)
of TiO2 particles. The presence of the OH on the surface of the catalyst is
In view of the above, the agglomeration was restricted, and evident by Fourier transform infrared (FTIR) where the OH
tiny nanoparticles were formed. Ionic liquid [BMIM BF4] on the stretching energy was shown at 3600 cm−1. From the above data,
surface of TiO2 may inhibit the adherence and agglomeration of in the current study, pH 2, 3, 4, 5, and 6 were varied while
tiny particles, leading to the production of smaller particles. An maintaining a CPT5IL2 catalyst dosage of 0.05 g and an Alizarin
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Figure 13. CPT5IL2 catalyst (a) ln(C/C0) vs time (b) catalyst dosages vs k (rate constant), Degradation %.

Figure 14. CPT5IL2 catalyst (a) ln(C/C0) vs time, (b) dye dosages vs k (rate constant), Degradation %, and (c) L-H curve.

Red S concentration of 5 mg/L (100 mL). According to Figures surface positive to bind the negative dye. At pH 2, protons
12(b) data and S15, the ideal free mean path between protons at experience electrostatic repulsion due to a substantial
pH 3 causes the degradation rate to be significantly higher, concentration of H+, resulting in a reduced free mean path
compared to the case at other pH values. Consequently, the among them. The process of degradation slows down at pH
proton can arrive at the surface and produce TiOH+2 , making the values of 4, 5 and 6, when fewer H+ are present.
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4.4. Optimization of the Catalyst Dose CPT5IL2. The Table 4. Comparative Efficiencies of Various Catalysts for
experiments were conducted with 0.05, 0.10, 0.15, 0.20, and 0.25 Alizarin Red S
g of catalyst, maintaining a pH of 3 and starting dye
Catalyst Source Degradation % Time Ref
concentration of 5 mg/L, which are shown in Figures 13 and 99
S16. The rate of reaction was enhanced up to 0.10 g, and later, it ZnO UV 77 90 min
100
decreased for the reaming doses of catalyst. This is attributed to Ni-WO3 UV 90.67 120 min
101
the fact that, even though increasing the catalyst dose, the dye Bi-TiO2 Visible 80 90 min
102
molecules are a fixed concentration, so the rate of degradation Cd-ZnS Visible 96.7 120 min
103
shall be constant. However, as the catalyst dosage is increased, ZnO UV A 99 120 min
the turbidity of the solution’s contents rises as well, delaying the CPT5IL2 Visible 98.2 60 min Present work
light’s ability to activate the catalyst particles.
4.5. Impact of ARS Dye Concentration. The most 15 depicts the zones of inhibition104 for two bacteria and one
effective starting dye concentration of Alizarin Red S was fungus, as the triplicate independently performed experimental
established by using the CPT5IL2 catalyst at a predetermined data listed in Table 5, when compared to their standards. The
dose of 0.10 gr and pH 3, changing the dye quantities as 5, 10, 15, antimicrobial activity response is proportional to the concen-
20, and 25 mg/L and given in Figures 14 (a), (b) and S17. The tration of the catalyst. The CPT5IL2 shows almost close values
figures show that the degradation process accelerated when the to standard references Chloramphenicol (for bacteria) and
amount of dye was raised to 10 mg/L.97 This can be explained by Fluconazole (for fungal) at 800 μg/mL. The degradation of the
the fact that as the concentration of the dye increased, more dye protein wall,105,106 which occurs when superoxide ions react
molecules became available for a fixed dose of catalyst. The with oxygen and water through the CPT5IL2 catalytic electron,
degradation rate falls when the dye concentration rises above the limits the proliferation of microbes.
indicated optimal concentrations. This is because the dye 4.7. Scavenger-Based Analysis for Identifying Photo-
functions as a blocking layer at a certain concentration, catalytic Species. It is essential to identify the active species
decreasing the amount of light that reaches the photocatalyst such as electron−hole, superoxide, and hydroxyl radicals
surface. produced during the reaction that boost the rate of photo-
To ascertain if the solid−liquid interface was the location that catalysis.
dominated the heterogeneous photocatalytic degradation, the 4.7.1. Inspect for Holes and Electrons. A 150 mL beaker with
Langmuir−Hinshelwood (LH) model was applied.98 The 0.10 g of CPT5IL2 catalyst at pH 3 and 10 mg/L dye was
description of the L-H model was as follows: exposed to visible light. Using a Millipore syringe, the dye
absorbance was measured at λmax 530 nm with 5 mL aliquots. A
1 C 1
= 0 + decrease in dye absorbance is noted, and 1.0 mL of 1 mM
k kLH kLHkL (5) disodium salt of EDTA was added to the beakers immediately.
Absorbance was calculated by taking aliquots every 5 min for 60
where C0 was the initial concentration of Alizarin Red S (mg/L), min, and Figure 16(a) shows the results. After 10 min, EDTA
kLH shows the L-H adsorption constant of ARS over the slowed the degradation process steadily. EDTA’s ability to hang
CPT5IL2 surface (g/L), kL is the intrinsic reaction rate constant onto the reaction mixture’s electron/hole was key to Alizarin
(mg min−1), and k is the pseudo-first-order rate constant Red S’s degradation.
(min−1). The plot in Figure 14(c) suggests that the experimental 4.7.2. Inspect for Superoxide Radicals. A 150 mL beaker
data fit well with the LH model (R2 = 0.998), indicating that the with 0.10 g of CPT5IL2 catalyst at pH 3 and 10 mg/L dye was
photocatalytic degradation of ARS primarily occurs at the brought to visible light. To measure dye absorbance, 5 mL
surface of CPT5IL2. Additionally, there is a directly propor- aliquots were taken by Millipore syringes. In response to the dye
tional linear relationship between 1/k and C0, suggesting that an absorbance decrease, 1,4-Benzoquinone was added promptly to
increase in initial ARS concentration may cause a decrease in the the reaction mixture. For the following half-hour, aliquots were
k value. Based on the slope and intercept, the values for kLH and sampled every 5 min to determine absorbance. Adding 1,4-
kL were determined to be 0.279 mg−1L and 0.013 L−1 min−1, benzoquinone reduced degradation, likely because it trapped
respectively. superoxide radicals (Figure 16(a)).
By following a thorough analysis of the reaction parameter 4.7.3. Inspect for Hydroxide Radicals. Hydroxyl radicals are
conditions, 0.10 g of CPT5IL2 catalyst was sufficient to hard to detect due to their short life span and high reactivity. The
complete the degradation of 10 mg/L dye Alizarin Red S at fluorescent coumarin molecule functions as a photolumines-
pH 3 and the degradation time was 60 min. By keeping these cence probe to identify the hydroxyl radical during photo-
conditions constant, the dye’s breakdown was completed in 60 catalysis. Coumarin solution was added to 0.10 g of CPT5IL2
min. These factors were used to compare the photocatalytic catalyst with 10 mg/L acidic pH 3 dye solution under light. 7-
efficiency with other study methodologies, which are displayed Hydroxy coumarin was formed when the coumarin molecule
in Table 4. and OH radicals interacted. A new compound has a maximum
4.6. Antimicrobial Activity. Two bacterial (Enterobacter fluorescence intensity peak at 450 nm. The fluorescence spectra
aerogenes (MTCC-241, Gram-negative), Salmonella typhimu- of 7-hydroxycoumarin were evaluated by taking a sample from
rium (MTCC-98, Gram-negative)) and one fungal (Candida the reaction mixture every 5 min (Figure 16(b)). Figure 16(b)
albicans (MTCC- 277, fungi)) strains were tested for shows that visible light increased the spectrum intensity. The
antimicrobial activity with the best catalyst CPT5IL2. The experiment showed that visible light stimulated CPT5IL2 to
Agar well diffusion method was used for this purpose. The bore produce OH radicals.
wells of Petri dishes stuffed with nutrient-rich broth have the 4.8. The Photocatalytic Mechanism of CPT5IL2 for the
CPT5IL2 catalyst added to them at concentrations of 400 μg/ Breakdown of Dyes and Antibacterial Activity. Reactive
mL, 600 μg/mL, 800 μg/mL, and 50 μg/mL as standards. Figure species play a critical role in the photocatalytic degradation of
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Figure 15. Antimicrobial activity with inhibition zone bar graphs.

Table 5. CPT5IL2 Catalyst Antimicrobial Activity Inhibition CPTiO2(s) + h CPTiO2(s)(h+) + CPTiO2(s)(e ) (6)
Zones Are Shown with Standards
Catalyst Dosage CPTiO2(s)(h+) + H 2O(aq)
50
400 600 800 (Std.) CPTiO2(s) + •OH(aq) + H(+aq) (7)
S.No Microbe Name μg/mL μg/mL μg/mL μg/mL
1 Enterobacter MEAN 19.07 22.03 24.02 26.01
aerogenes CPTiO2(s)(h+) + OH(aq) CPTiO2(s) + •OH(aq) (8)
SD 0.15 0.08 0.07 0.01
(MTCC-241)
2 Salmonella MEAN 16.05 18.00 19.87 22.00 CPTiO2(s)(e ) + O2(aq) CPTiO2(s) + O2 (aq)
typhimurium SD 0.03 0.07 0.32 0.02 (9)
(MTCC-98)
3 Candida albicans MEAN 11.03 13.01 14.03 16.03
(MTCC- 277) CPTiO2(s)(e ) + O2 + H 2O(aq)
SD 0.04 0.03 0.07 0.02
CPTiO2(s) + HO•2(aq) + OH (aq) (10)

dye, a model pollutant, as shown by scavenging tests. Hydroxyl CPTiO2(s)(e ) + HO•2(aq) + H+(aq)
radicals •OH are essential active species in degrading organic
contaminants. When the CPT5IL2 catalyst is exposed to visible CPTiO2(s) + H 2O2(aq) (11)
light, electrons in the valence band gain energy and move to the
conduction band, creating holes (eq 6). These holes react with CPTiO2(s)(e ) + H 2O2(aq)
surface hydroxyl groups and adsorbed water molecules to
produce •OH and H+ (eqs 7 and 8). Superoxide anion (O2−) is CPTiO2(s) + •OH(aq) + OH (aq) (12)
generated when adsorbed oxygen (O2) accepts electrons.
Adsorbed water molecules react to form hydroxyl ions (OH−) Mineralization
and hydroperoxide radicals (HO•2), as shown in eqs 9 and 10. Alizarin Red S Dye(ARS) + •OH CO2 + H 2O
The H+ ions and HO•2 then react to produce hydroxyl ions (13)
(OH−) and hydroxyl radicals (•OH), as indicated in eqs 11 and •
12. These radicals are responsible for degrading dyes and OH
Microbes + Destruction of Microbe growth
destroying microbes (eqs 13 and 14). The concise photo- h+
catalytic mechanism is given in Figure 17. (14)

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Figure 16. (a) Scavenger effect for e−/h+ and O2−. (b) Photoluminescence spectra of the •OH scavenger.

catalyst component from the dye solution before recycling. A

hot air oven set at 70 °C was used to dry the catalyst after it had
been washed with ultrapure ethanol. There was a modest
decrease in degradation when the same catalyst sample was
recycled again, as seen by the C/C0 versus time plot for five
cycles shown in Figure 18(a). Possible causes for this include
dye adsorption capacity and catalytic loss during the washing
process.
The crystal structure remained unaltered, as found in the XRD
investigation, as Figure 18(b) illustrates the anatase 2θ values
remaining unchanged.

5. CONCLUSION
Figure 17. Graphical image of photocatalytic mechanism. (Artwork Using an ionic liquid (BMIM BF4) as a capping agent, the Ce
courtesy of “Nageswara Rao Kadiyala”. Copyright 2024.) and Phosphorus doped TiO2 was produced successfully using
the modified sol−gel technique. These catalysts can be
4.9. Durability Test of CPT5IL2. For the past few years, characterized by PXRD, FTIR, XRF, UV−visible DRS, PL,
photocatalysis has not received much attention if it cannot be TCSPC, EIS, TEM, BET, and SEM-EDX. The structure and
recycled. The design of the process is primarily responsible for activity of the photocatalysts have been found to be significantly
enabling the catalyst to keep its intended qualities, which in turn impacted by scissoring agents and doping. The particle size or
determines the catalyst’s stability, efficiency of recycling, and crystallite size of the doped samples reduced as the surface area
recovery. For the catalyst CPT5IL2, five cycles were run under grew in line with a rise in Ce content in the catalyst. The addition
optimal conditions to ascertain how long it will last under the of Ce and P to TiO2 resulted in a decrease in electron and hole
same condition. The first cycle involved extracting the solid recombination, as evidenced by the low charge transfer

Figure 18. After 5 cycles, CPT5IL2 catalyst (a) degradation %, and (b) PXRD.

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resistance from PL, TCSPC, and EIS. These findings were

corroborated by the FTIR analysis of the prepared catalysts,
■ ACKNOWLEDGMENTS
The authors thank the SAIF, IIT Bombay, India, for providing
which also showed an increase in the number of hydroxyl ions on the Time Resolved Fluorescence Spectroscopy and Microscopy
the surface with the ionic liquid capping agent. The codoped facility.
samples’ photocatalytic efficiency was tested by Alizarin Red S
degradation under visible light. The 10 mg/L Alizarin Red S dye
concentration was degraded in 60 min by the catalyst CPT5IL2
■ REFERENCES
(1) Rambaran, T.; Schirhagl, R. Nanotechnology from lab to industry
at a pH of 3 with a quantity of 0.10 g. Furthermore, it − a look at current trends. Nanoscale Advances 2022, 4, 3664−3675.
demonstrates antimicrobial efficacy against Enterobacter aero- (2) Khan, I.; Saeed, K.; Khan, I. Nanoparticles: Properties,
applications and toxicities. Arabian Journal of Chemistry 2019, 12,
genes (MTCC-241), Salmonella typhimurium (MTCC-98, 908−931.
gramme -ve), and Candida albicans (MTCC- 277). (3) Schneider, J.; Matsuoka, M.; Takeuchi, M.; Zhang, J.; Horiuchi, Y.;
Anpo, M.; Bahnemann, D. W. Understanding TiO2 Photocatalysis:
■
*
ASSOCIATED CONTENT
sı Supporting Information
Mechanisms and Materials. Chem. Rev. 2014, 114, 9919−9986.
(4) Fujishima, A.; Rao, T. N.; Tryk, D. A. Titanium dioxide
photocatalysis. Journal of Photochemistry and Photobiology C: Photo-
The Supporting Information is available free of charge at chemistry Reviews 2000, 1, 1−21.
https://pubs.acs.org/doi/10.1021/acsomega.4c07743. (5) Nazeeruddin, M. K.; Kay, A.; Rodicio, I.; Humphry-Baker, R.;
Mueller, E.; Liska, P.; Vlachopoulos, N.; Graetzel, M. Conversion of
Rietveld refinement fitting of XRD pattern of four light to electricity by cis-X2bis(2,2’-bipyridyl-4,4’-dicarboxylate)-
catalysts; Goodness of Fit parameters for the Rietveld ruthenium(II) charge-transfer sensitizers (X = Cl−, Br−, I−, CN−, and
refinement analysis; UV−Vis DRS absorption spectra of SCN−) on nanocrystalline titanium dioxide electrodes. J. Am. Chem.
all catalysts; VBXP spectra of PT, CPT5 and CPT5IL2; Soc. 1993, 115, 6382−6390.
(6) Garg, A.; Singhania, T.; Singh, A.; Sharma, S.; Rani, S.; Neogy, A.;
CPT5IL1 catalyst SEM, TEM analysis; CPT5IL3 catalyst Yadav, S.R.; Sangal, V.K.; Garg, N. Photocatalytic Degradation of
SEM, TEM analysis; CPT5IL4 catalyst SEM, TEM Bisphenol-A using N, Co Codoped TiO2 Catalyst under Solar Light.
analysis; EDx and elemental mappings of PT, CPT5, Scientific Reports 2019, 9, DOI: 10.1038/s41598-018-38358-w.
and CPT5IL2, High Resolution Spectra of all the catalysts (7) Gupta, K.; Singh, R. P.; Pandey, A.; Pandey, A. Correction:
for Ti, O, Ce, and P; FTIR Spectra for all the catalysts; Photocatalytic antibacterial performance of TiO2 and Ag-doped TiO2
Alizarin Red S (ARS) dye Degradation graph of all CPT against S. aureus. P. aeruginosa and E. coli. Beilstein Journal of
catatysts; ARS dye Degradation graph of CPT5IL2 at pH Nanotechnology 2020, 11, 547−549.
= 2, 3, 4, 5 and 6; ARS dye Degradation graph of CPT5IL2 (8) Jaiswal, R.; Patel, N.; Kothari, D. C.; Miotello, A. Improved visible
at different catalyst dosages; Degradation graph of ARS by light photocatalytic activity of TiO2 co-doped with Vanadium and
varying dye concentration by CPT5IL2 Catalyst; BMIM Nitrogen. Applied Catalysis B: Environmental 2012, 126, 47−54.
BF4 and Alizarin Red S diagrams. (DOCX) (9) Jing, D.; Zhang, Y.; Guo, L. Study on the synthesis of Ni doped
mesoporous TiO2 and its photocatalytic activity for hydrogen evolution
in aqueous methanol solution. Chem. Phys. Lett. 2005, 415, 74−78.

■ AUTHOR INFORMATION
Corresponding Author
(10) Ansari, S.A.; Khan, M.M.; Ansari, M.O.; Cho, M.H. Nitrogen-
Doped Titanium Dioxide (N-Doped TiO2) for Visible Light Photo-
catalysis. New J. Chem. 2016, 40, DOI: 10.1039/C5NJ03478G.
Siva Rao Tirukkovalluri − Department of Chemistry, Andhra (11) Arunmetha, S.; Dhineshbabu, N. R.; Kumar, A.; Jayavel, R.
Preparation of sulfur doped TiO2 nanoparticles from rutile sand and
University, Visakhapatnam, Andhra Pradesh 530003, India;
their performance testing in hybrid solar cells. Journal of Materials
orcid.org/0000-0001-5156-1885; Phone: 7702110459; Science: Materials in Electronics 2021, 32, 28382−28393.
Email: sivaraoau@gmail.com (12) Choi, W.; Termin, A.; Hoffmann, M. R. The Role of Metal Ion
Dopants in Quantum-Sized TiO2: Correlation between Photoreactivity
Authors and Charge Carrier Recombination Dynamics. J. Phys. Chem. 1994, 98,
Nageswararao Kadiyala − Department of Chemistry, Dr. V. S. 13669−13679.
Krishna Govt. Degree College (A), Maddilapalem, (13) Demeestere, K.; Dewulf, J.; Ohno, T.; Salgado, P. H.; Van
Visakhapatnam, Andhra Pradesh 530013, India Langenhove, H. Visible light mediated photocatalytic degradation of
Divya Gorli − Department of Chemistry, Andhra University, gaseous trichloroethylene and dimethyl sulfide on modified titanium
Visakhapatnam, Andhra Pradesh 530003, India dioxide. Applied Catalysis B: Environmental 2005, 61, 140−149.
Jaishree Genji − Department of Chemistry, Andhra University, (14) Pelaez, M.; Nolan, N. T.; Pillai, S. C.; Seery, M. K.; Falaras, P.;
Visakhapatnam, Andhra Pradesh 530003, India Kontos, A. G.; Dunlop, P. S. M.; Hamilton, J. W. J.; Byrne, J. A.; O’Shea,
Raffiunnisa − Aditya College of Engineering, Department of K.; Entezari, M. H.; Dionysiou, D. D. A review on the visible light active
titanium dioxide photocatalysts for environmental applications. Applied
Chemistry, Surampalem, Andhra Pradesh 533437, India Catalysis B: Environmental 2012, 125, 331−349.
Ravichandra Matangi − Department of Chemistry, Indian (15) Navio, J.; Colon, G.; Litter, M. I.; Bianco, G. N. Synthesis,
Institute of Technology Patna, Bihta, Bihar 801106, India characterization and photocatalytic properties of iron-doped titania
Sai Supriya Singupilla − Department of Chemistry, Andhra semiconductors prepared from TiO2 and iron(III) acetylacetonate. J.
University, Visakhapatnam, Andhra Pradesh 530003, India Mol. Catal. A: Chem. 1996, 106, 267−276.
Complete contact information is available at: (16) Romualdo Torres, G.; Lindgren, T.; Lu, J.; Granqvist, C.;
Lindquist, S. Photoelectrochemical Study of Nitrogen-Doped Titanium
https://pubs.acs.org/10.1021/acsomega.4c07743
Dioxide for Water Oxidation. J. Phys. Chem. B. 2004, 108, 5995−6003
DOI: 10.1021/jp037477s.
Notes (17) Dong, F.; Guo, S.; Wang, H.; Li, X.; Wu, Z. Enhancement of the
The authors declare no competing financial interest. Visible Light Photocatalytic Activity of C-Doped TiO2 Nanomaterials

R https://doi.org/10.1021/acsomega.4c07743
ACS Omega XXXX, XXX, XXX−XXX
ACS Omega http://pubs.acs.org/journal/acsodf Article

Prepared by a Green Synthetic Approach. J. Phys. Chem. C 2011, 115, (36) Shi, Q.; Yang, D.; Jiang, Z.; Li, J. Visible-light photocatalytic
13285−13292. regeneration of NADH using P-doped TiO2 nanoparticles. Journal of
(18) Birlik, I.; Dagdelen, D. Synergistic effect of manganese and Molecular Catalysis B: Enzymatic 2006, 43, 44−48.
nitrogen codoping on photocatalytic properties of titania nanoparticles. (37) LIN, L.; LIN, W.; XIE, J.; ZHU, Y.; ZHAO, B.; XIE, Y.
Bulletin of Materials Science. 2020, 43, DOI: 10.1007/s12034-020- Photocatalytic properties of phosphor-doped titania nanoparticles.
2041-8. Applied Catalysis B: Environmental 2007, 75, 52−58.
(19) Wang, Y.; Huang, L.; Zhang, T. C.; Wang, Y.; Yuan, S. Visible- (38) MOHAMED, R. M.; AAZAM, E. Synthesis and characterization
Light-Induced photocatalytic oxidation of gaseous ammonia on Mo, C- of P-doped TiO2 thin-films for photocatalytic degradation of butyl
codoped TiO2: Synthesis, performance and mechanism. Chemical benzyl phthalate under visible-light irradiation. Chinese Journal of
Engineering Journal 2024, 482, No. 148811. Catalysis 2013, 34, 1267−1273.
(20) Nasir, M.; Xi, Z.; Xing, M.; Zhang, J.; Chen, F.; Tian, B.; Bagwasi, (39) Li, F.; Jiang, Y.; Xia, M.; Sun, M.; Xue, B.; Liu, D.; Zhang, X.
S. Study of Synergistic Effect of Ce- and S-Codoping on the Effect of the P/Ti Ratio on the Visible-Light Photocatalytic Activity of
Enhancement of Visible-Light Photocatalytic Activity of TiO2. J. Phys. P-Doped TiO2. J. Phys. Chem. C 2009, 113, 18134−18141.
Chem. C 2013, 117, 9520−9528. (40) Kamisaka, H.; Yamashita, K. Theoretical Study of the Interstitial
(21) Yu, X.; Gao, C.; Liu, J.; Wang, J.; Jia, M.; Sa, G.; Xu, A. Electronic Oxygen Atom in Anatase and Rutile TiO2: Electron Trapping and
and photocatalytic properties of N, V co-doped anatase TiO2. Vacuum Elongation of the r(O−O) Bond. J. Phys. Chem. C 2011, 115, 8265−
2024, 222, No. 113001. 8273.
(22) Kumar, R.; Swain, G.; Dutta, S. Synthesis of visible light-sensitive (41) Cheng, H.; Wang, J.; Zhao, Y.; Han, X. Effect of phase
photocatalysts for hydrogen production. Fuel 2024, 360, No. 130555. composition, morphology, and specific surface area on the photo-
(23) Nasir, M.; Bagwasi, S.; Jiao, Y.; Chen, F.; Tian, B.; Zhang, J. catalytic activity of TiO2 nanomaterials. RSC Adv. 2014, 4, 47031−
Characterization and activity of the Ce and N co-doped TiO2 prepared 47038.
through hydrothermal method. Chemical Engineering Journal 2014, 236, (42) Liu, J. W.; Han, R.; Wang, H. T.; Zhao, Y.; Chu, Z.; Wu, H. Y.
388−397. Photoassisted degradation of pentachlorophenol in a simulated soil
(24) Makdee, A.; Unwiset, P.; Chanapattharapol, K. C.; Kidkhunthod, washing system containing nonionic surfactant Triton X-100 with La−
P. Effects of Ce addition on the properties and photocatalytic activity of B codoped TiO2 under visible and solar light irradiation. Applied
TiO2, investigated by X-ray absorption spectroscopy. Mater. Chem. Catalysis B: Environmental 2011, 103, 470−478.
Phys. 2018, 213, 431−443. (43) Feilizadeh, M.; Vossoughi, M.; Zakeri, S. M. E.; Rahimi, M.
(25) Reli, M.; Ambrožová, N.; Š ihor, M.; Matějová, L.; Č apek, L.; Enhancement of Efficient Ag−S/TiO2 Nanophotocatalyst for Photo-
Obalová, L.; Matěj, Z.; Kotarba, A.; Kočí, K. Novel cerium doped titania catalytic Degradation under Visible Light. Ind. Eng. Chem. Res. 2014, 53,
catalysts for photocatalytic decomposition of ammonia. Applied 9578−9586.
Catalysis B: Environmental 2015, 178, 108−116. (44) Liu, H.; Liang, Y.; Hu, H.; Wang, M. Hydrothermal synthesis of
(26) Lee; Choi. Sonochemical Synthesis of Ce-doped TiO 2 mesostructured nanocrystalline TiO2 in an ionic liquid−water mixture
Nanostructure: A Visible-Light-Driven Photocatalyst for Degradation and its photocatalytic performance. Solid State Sci. 2009, 11, 1655−
of Toluene and O-Xylene. Materials 2019, 12, 1265. 1660.
(27) Silva, A. M. T.; Silva, C. G.; Dražić, G.; Faria, J. L. Ce-doped TiO2 (45) Zhang, Y.; Liu, W.; Chen, S.; Gao, Q.; Li, Q.; Zhu, X. Ionic liquids
for photocatalytic degradation of chlorophenol. Catal. Today 2009, for the controllable preparation of functional TiO2 nanostructures: a
144, 13−18. review. Ionics 2020, 26, 5853−5877.
(28) Fan, Z.; Meng, F.; Gong, J.; Li, H.; Ding, Z.; Ding, B. One-step (46) Eshetu, G. G.; Armand, M.; Ohno, H.; Scrosati, B.; Passerini, S.
hydrothermal synthesis of mesoporous Ce-doped anatase TiO2 Ionic liquids as tailored media for the synthesis and processing of energy
nanoparticles with enhanced photocatalytic activity. Journal of Materials conversion materials. Energy Environ. Sci. 2016, 9, 49−61.
Science: Materials in Electronics 2016, 27, 11866−11872. (47) Kim, T. Y.; Kim, W. J.; Hong, S. H.; Kim, J. E.; Suh, K. S. Ionic-
(29) Jafari, A.; Khademi, S.; Farahmandjou, M.; Darudi, A.; Rasuli, R. Liquid-Assisted Formation of Silver Nanowires. Angew. Chem. 2009,
Structural and Optical Properties of Ce3+-Doped TiO2 Nanocrystals 121, 3864−3867.
Prepared by Sol−Gel Precursors. J. Electron. Mater. 2018, 47, 6901− (48) Dong, W.-S.; Li, M.-Y.; Liu, C.; Lin, F.; Liu, Z. Novel ionic liquid
6908. assisted synthesis of SnO2 microspheres. J. Colloid Interface Sci. 2008,
(30) Dutta, G.; Waghmare, U. V.; Baidya, T.; Hegde, M. S.; Priolkar, 319, 115−122.
K. R.; Sarode, P. R. Reducibility of Ce1‑x Zrx O2: Origin of Enhanced (49) Ionic liquids for nano- and microstructures preparation. Part 1:
Oxygen Storage Capacity. Catal. Lett. 2006, 108, 165−172. Properties multifunctional role, 2015. DOI: 10.1016/j.cis.2015.08.006.
(31) Shayegan, Z.; Haghighat, F.; Lee, C.-S. Surface fluorinated Ce- (50) Hammond, O. S.; Mudring, A.-V. Ionic liquids and deep eutectics
doped TiO2 nanostructure photocatalyst: A trap and remove strategy to as a transformative platform for the synthesis of nanomaterials. Chem.
enhance the VOC removal from indoor air environment. Chemical Commun. 2022, 58, 3865−3892.
Engineering Journal 2020, 401, No. 125932. (51) Zheng, W.; Liu, X.; Yan, Z.; Zhu, L. Ionic Liquid-Assisted
(32) Gopal, N. O.; Lo, H.-H.; Ke, T.-F.; Lee, C.-H.; Chou, C.-C.; Wu, Synthesis of Large-Scale TiO2 Nanoparticles with Controllable Phase
J.-D.; Sheu, S.-C.; Ke, S.-C. Visible Light Active Phosphorus-Doped by Hydrolysis of TiCl4. ACS Nano 2009, 3, 115−122.
TiO2 Nanoparticles: An EPR Evidence for the Enhanced Charge (52) Yoo, K.; Choi, H.; Dionysiou, D. D. Ionic liquid assisted
Separation. J. Phys. Chem. C 2012, 116, 16191−16197. preparation of nanostructured TiO2 particles. Chem. Commun. 2004,
(33) Mendiola-Alvarez, S. Y.; Hernández-Ramírez, Ma.A.; Guzmán- 2000.
Mar, J. L.; Garza-Tovar, L. L.; Hinojosa-Reyes, L. Phosphorous-doped (53) Liu, H.; Liang, Y.; Hu, H.; Wang, M. Hydrothermal synthesis of
TiO2 nanoparticles: synthesis, characterization, and visible photo- mesostructured nanocrystalline TiO2 in an ionic liquid−water mixture
catalytic evaluation on sulfamethazine degradation. Environmental and its photocatalytic performance. Solid State Sci. 2009, 11, 1655−
Science and Pollution Research 2019, 26, 4180−4191. 1660.
(34) Rescigno, R.; Sacco, O.; Venditto, V.; Fusco, A.; Donnarumma, (54) Zhang, Y.; Liu, W.; Chen, S.; Gao, Q.; Li, Q.; Zhu, X. Ionic liquids
G.; Lettieri, M.; Fittipaldi, R.; Vaiano, V. Photocatalytic activity of P- for the controllable preparation of functional TiO2 nanostructures: a
doped TiO2 photocatalyst. Photochemical & Photobiological Sciences review. Ionics 2020, 26, 5853−5877.
2023, 22, 1223−1231. (55) Ionic liquids for nano- and microstructures preparation. Part 2:
(35) Ansari, S.A.; Cho, M.H. Highly Visible Light Responsive, Narrow Application in synthesis, 2015. DOI: 10.1016/j.cis.2015.08.010.
Band gap TiO2 Nanoparticles Modified by Elemental Red Phosphorus (56) Tapak, N. S.; Nawawi, M. A.; Mohamed, A. H.; Tjih, E. T. T.;
for Photocatalysis and Photoelectrochemical Applications. Scientific Mohd, Y.; Ab Rashid, A. H. B.; Abdullah, J.; Yusof, N. A.; Ahmad, N. M.
Reports 2016, 6, DOI: 10.1038/srep25405. Chemical synthesis of metal oxide nanoparticles via ionic liquid as

S https://doi.org/10.1021/acsomega.4c07743
ACS Omega XXXX, XXX, XXX−XXX
ACS Omega http://pubs.acs.org/journal/acsodf Article

capping agent: Principle, preparation and applications. Malaysian. (76) Mandujano-Ramírez, H. J.; González-Vázquez, J. P.; Oskam, G.;
Journal of Analytical sciences 2022, 26, 1394−1420. Dittrich, T.; Garcia-Belmonte, G.; Mora-Seró, I.; Bisquert, J.; Anta, J. A.
(57) Pirillo, S.; Ferreira, M. L.; Rueda, E. H. The effect of pH in the Charge separation at disordered semiconductor heterojunctions from
adsorption of Alizarin and Eriochrome Blue Black R onto iron oxides. random walk numerical simulations. Phys. Chem. Chem. Phys. 2014, 16,
Journal of Hazardous Materials 2009, 168, 168−178. 4082.
(58) Kansal, S. K.; Lamba, R.; Mehta, S. K.; Umar, A. Photocatalytic (77) Chanda, N.; Koteshwar, D.; Gonuguntla, S.; Bojja, S.; Pal, U.;
degradation of Alizarin Red S using simply synthesized ZnO Giribabu, L. Efficient visible-light-driven hydrogen production by Zn−
nanoparticles. Mater. Lett. 2013, 106, 385−389. porphyrin based photocatalyst with engineered active donor−acceptor
(59) Tortora, G.J.; Funke, B.R.; Case, C.L. Microbiology: An sites. Materials Advances 2021, 2, 4762−4771.
Introduction; Benjamin Cummings Pub, 2010. (78) Chen, H.; Zhu, W.; Zhang, Z.; Cai, W.; Zhou, X. Er and Mg co-
(60) Leite, M. C. A.; Bezerra, A. P. d. B.; Sousa, J. P. d.; Guerra, F. Q. doped TiO2 nanorod arrays and improvement of photovoltaic property
S.; Lima, E. d. O. Evaluation of Antifungal Activity and Mechanism of in perovskite solar cell. J. Alloy. Compd. 2019, 771, 649−657.
Action of Citral againstCandida albicans. Evidence-Based Complemen- (79) Burungale, V. V.; Satale, V. V.; More, A. J.; Sharma, K. K. K.;
tary and Alternative Medicine 2014, 2014, 1−9. Kamble, A. S.; Kim, J. H.; Patil, P. S. Studies on effect of temperature on
(61) Zhang, X.; Luo, L.; Duana, Z. Preparation and application of Ce- synthesis of hierarchical TiO2 nanostructures by surfactant free single
doped mesoporous TiO2 oxide. React. Kinet. Catal. Lett. 2005, 87, 43− step hydrothermal route and its photoelectrochemical character-
50. izations. J. Colloid Interface Sci. 2016, 470, 108−116.
(62) Dosa, M.; Piumetti, M.; Bensaid, S.; Andana, T.; Galletti, C.; (80) John, S.; Vadla, S. S.; Roy, S. C. High photoelectrochemical
Fino, D.; Russo, N. Photocatalytic Abatement of Volatile Organic activity of CuO nanoflakes grown on Cu foil. Electrochim. Acta 2019,
Compounds by TiO2 Nanoparticles Doped with Either Phosphorous or 319, 390−399.
Zirconium. Materials 2019, 12, 2121. (81) Pan, X.; Zhao, Y.; Liu, S.; Korzeniewski, C. L.; Wang, S.; Fan, Z.
(63) Xie, J.; Jiang, D.; Chen, M.; Li, D.; Zhu, J.; Lü, X.; Yan, C. Comparing graphene TiO2 nanowire and graphene- TiO2 nanoparticle
Preparation and characterization of monodisperse Ce-doped TiO2 composite photocatalysts. ACS Appl. Mater. Interfaces 2012, 4, 3944−
microspheres with visible light photocatalytic activity. Colloids Surf., A 3950.
2010, 372, 107−114. (82) Wang, Y.; Zhang, Y. Y.; Tang, J.; Wu, H.; Xu, M.; Peng, Z.; Gong,
(64) Š tengl, V.; Bakardjieva, S.; Murafa, N. Preparation and X. G.; Zheng, G. Simultaneous etching and doping of TiO2 nanowire
photocatalytic activity of rare earth doped TiO2 nanoparticles. Mater. arrays for enhanced photoelectrochemical performance. ACS Nano
Chem. Phys. 2009, 114, 217−226. 2013, 7, 9375−9383.
(65) Li, F. B.; Li, X. Z.; Hou, M. F.; Cheah, K. W.; Choy, W. C. H. (83) Gao, Y.; Xu, J.; Shi, S.; Dong, H.; Cheng, Y.; Wei, C.; Zhang, X.;
Enhanced photocatalytic activity of Ce3+− TiO2 for 2-mercaptobenzo- Yin, S.; Li, L. TiO2 nanorod arrays based self-powered UV
thiazole degradation in aqueous suspension for odour control. Applied photodetector: heterojunction with NiO nano flakes and enhanced
Catalysis A: General 2005, 285, 181−189. UV photoresponse. ACS Appl. Mater. Interfaces 2018, 10, 11269−
(66) Padmini, E.; Miranda, L. R. Nanocatalyst from sol−sol doping of 11279.
TiO2 with Vanadium and Cerium and its application for 3,4 (84) Sang, L.; Tan, H.; Zhang, X.; Wu, Y.; Ma, C.; Burda, C. Effect of
Dichloroaniline degradation using visible light. Chemical Engineering quantum dot deposition on the interfacial flatband potential, depletion
Journal 2013, 232, 249−258. layer in TiO2 nanotube electrodes, and resulting H2 generation rates. J.
(67) Hao, C.; Li, J.; Zhang, Z.; Ji, Y.; Zhan, H.; Xiao, F.; Wang, D.; Liu, Phys. Chem. C 2012, 116, 18633−18640.
B.; Su, F. Enhancement of photocatalytic properties of TiO2 (85) Zhang, H.; Xing, Z.; Zhang, Y.; Li, Z.; Wu, X.; Liu, C.; Zhu, Q.;
nanoparticles doped with CeO2 and supported on SiO2 for phenol Zhou, W. Ni2+ and Ti3+ co-doped porous black anatase TiO2 with
degradation. Appl. Surf. Sci. 2015, 331, 17−26. unprecedented-high visible-light-driven photocatalytic degradation
(68) Pan, J.; Liu, G.; Lu, G. Q.; Cheng, H. On the True Photoreactivity performance. RSC Adv. 2015, 5, 107150−107157.
Order of {001}, {010}, and {101} Facets of Anatase TiO2 Crystals. (86) Zhang, H.; Xing, Z.; Zhang, Y.; Li, Z.; Wu, X.; Liu, C.; Zhu, Q.;
Angew. Chem. 2011, 50, 2133−2137. Zhou, W. Ni2+ and Ti3+ co-doped porous black anatase TiO2 with
(69) Lu, L.; Shan, R.; Shi, Y.; Wang, S.; Yuan, H. A novel TiO2/ unprecedented-high visible-light-driven photocatalytic degradation
biochar composite catalysts for photocatalytic degradation of methyl performance. RSC Adv. 2015, 5, 107150−107157.
orange. Chemosphere 2019, 222, 391−398. (87) Wang, B.; Zhang, G.; Sun, Z.; Zheng, S.; Frost, R. L. A
(70) Jiang, X.; Zhang, Y.; Jiang, J.; Rong, Y.; Wang, Y.; Wu, Y.; Pan, C. comparative study about the influence of metal ions (Ce, La and V)
Characterization of Oxygen Vacancy Associates within Hydrogenated doping on the solar-light-induced photodegradation toward rhodamine
TiO2: A Positron Annihilation Study. J. Phys. Chem. C 2012, 116, B. Journal of Environmental Chemical Engineering 2015, 3, 1444−1451.
22619−22624. (88) Liu, Y.; Fang, P.; Cheng, Y.; Gao, Y.; Chen, F.; Liu, Z.; Dai, Y.
(71) Kayani, Z. N.; Maria; Riaz, S.; Naseem, S. Magnetic and Study on enhanced photocatalytic performance of cerium doped TiO2-
antibacterial studies of sol-gel dip coated Ce doped TiO2 thin films: based nanosheets. Chemical Engineering Journal 2013, 219, 478−485.
Influence of Ce contents. Ceram. Int. 2020, 46, 381−390. (89) Deng, C.; Li, B.; Dong, L.; Zhang, F.; Fan, M.; Jin, G.; Gao, J.;
(72) Kaur, J.; Singh, R.; Pal, B. Influence of coinage and platinum Gao, L.; Zhang, F.; Zhou, X. NO reduction by CO over CuO supported
group metal co-catalysis for the photocatalytic reduction of m- on CeO2-doped TiO2: the effect of the amount of a few CeO2. Physical
dinitrobenzene by P25 and rutile TiO2. J. Mol. Catal. A: Chem. 2015, Chemistry Chemical Physics/PCCP. Physical Chemistry Chemical Physics
397, 99−105. 2015, 17, 16092−16109.
(73) He, Z.; Zhu, Z.; Li, J.; Zhou, J.; Wei, N. Characterization and (90) Song, S.; Tu, J.; Xu, L.; Xu, X.; He, Z.; Qiu, J.; Ni, J.; Chen, J.
activity of mesoporous titanium dioxide beads with high surface areas Preparation of a titanium dioxide photocatalyst codoped with cerium
and controllable pore sizes. Journal of Hazardous Materials 2011, 190, and iodine and its performance in the degradation of oxalic acid.
133−139. Chemosphere 2008, 73, 1401−1406.
(74) Tripathi, A. K.; Singh, M. K.; Mathpal, M. C.; Mishra, S. K.; (91) Demirci, S.; Dikici, T.; Yurddaskal, M.; Gultekin, S.; Toparli, M.;
Agarwal, A. Study of structural transformation in TiO2 nanoparticles Celik, E. Synthesis and characterization of Ag doped TiO 2
and its optical properties. J. Alloys Compd. 2013, 549, 114−120. heterojunction films and their photocatalytic performances. Appl.
(75) Divya, K. S.; Xavier, M. M.; Vandana, P. V.; Reethu, V. N.; Surf. Sci. 2016, 390, 591−601.
Suresh, M. A quaternary TiO2/ZnO/RGO/Ag nanocomposite with (92) Lei, X. F.; Xue, X. X.; Yang, H. Preparation and characterization
enhanced visible light photocatalytic performance. New J. Chem. 2017, of Ag-doped TiO2 nanomaterials and their photocatalytic reduction of
41, 6445−6454. Cr(VI) under visible light. Appl. Surf. Sci. 2014, 321, 396−403.

T https://doi.org/10.1021/acsomega.4c07743
ACS Omega XXXX, XXX, XXX−XXX
ACS Omega http://pubs.acs.org/journal/acsodf Article

(93) Lu, H.; Zhuang, J.; Ma, Z.; Zhou, W.; Xia, H.; Xiao, Z.; Zhang, H.;
Li, H. Crystal recombination control by using Ce doped in mesoporous
TiO2for efficient perovskite solar cells. RSC Adv. 2019, 9, 1075−1083.
(94) Kaur, R.; Singla, P.; Singh, K. Transition metals (Mn, Ni, Co)
doping in TiO2 nanoparticles and their effect on degradation of diethyl
phthalate. International Journal of Environmental Science and Technology
2018, 15, 2359−2368.
(95) Fang, Z.; Thanthiriwatte, K. S.; Dixon, D. A.; Andrews, L.; Wang,
X. Properties of Cerium Hydroxides from Matrix Infrared Spectra and
Electronic Structure Calculations. Inorg. Chem. 2016, 55, 1702−1714.
(96) Choina, J.; Kosslick, H.; Fischer, Ch.; Flechsig, G.-U.; Frunza, L.;
Schulz, A. Photocatalytic decomposition of pharmaceutical ibuprofen
pollutions in water over titania catalyst. Applied Catalysis B:
Environmental 2013, 129, 589−598.
(97) Vilhunen, S.; Bosund, M.; Kääriäinen, M.-L.; Cameron, D.;
Sillanpää, M. Atomic layer deposited TiO2 films in photodegradation of
aqueous salicylic acid. Sep. Purif. Technol. 2009, 66, 130−134.
(98) Wang, F.; Feng, Y.; Chen, P.; Wang, Y.; Su, Y.; Zhang, Q.; Zeng,
Y.; Xie, Z.; Liu, H.; Liu, Y.; Lv, W.; Liu, G. Photocatalytic degradation of
fluoroquinolone antibiotics using ordered mesoporous g-C3N4 under
simulated sunlight irradiation: Kinetics, mechanism, and antibacterial
activity elimination. Applied Catalysis. B, Environmental 2018, 227,
114−122.
(99) Kansal, S. K.; Lamba, R.; Mehta, S. K.; Umar, A. Photocatalytic
degradation of Alizarin Red S using simply synthesized ZnO
nanoparticles. Mater. Lett. 2013, 106, 385−389.
(100) Santhi, K.; Rani, C.; Karuppuchamy, S. Degradation of Alizarin
Red S dye using Ni doped WO3 photocatalyst. Journal of Materials
Science: Materials in Electronics 2016, 27, 5033−5038.
(101) Sood, S.; Mehta, S. K.; Umar, A.; Kansal, S. K. The visible light-
driven photocatalytic degradation of Alizarin red S using Bi-doped TiO2
nanoparticles. New J. Chem. 2014, 38, 3127−3136.
(102) Jabeen, U.; Shah, S. M.; Khan, S. U. Photo catalytic degradation
of Alizarin red S using ZnS and cadmium doped ZnS nanoparticles
under unfiltered sunlight. Surfaces and Interfaces 2017, 6, 40−49.
(103) Sharma, S. C. ZnO nano-flowers from Carica papaya milk:
Degradation of Alizarin Red-S dye and antibacterial activity against
Pseudomonas aeruginosa and Staphylococcus aureus. Optik 2016, 127,
6498−6512.
(104) Ashfaq, A.; Ikram, M.; Haider, A.; Ul-Hamid, A.; Shahzadi, I.;
Haider, J. Nitrogen and Carbon Nitride-Doped TiO2 for Multiple
Catalysis and Its Antimicrobial Activity, Nanoscale Research Letters.
2021, 16, DOI: 10.1186/s11671-021-03573-4.
(105) Haider, A.; Ijaz, M.; Ali, S.; Haider, J.; Imran, M.; Majeed, H.;
Shahzadi, I.; Ali, M.M.; Khan, J.A.; Ikram, M. Green Synthesized
Phytochemically (Zingiber officinale and Allium sativum) Reduced
Nickel Oxide Nanoparticles Confirmed Bactericidal and Catalytic
Potential. Nanoscale Res. Lett. 2020, 15, DOI: 10.1186/s11671-020-
3283-5.
(106) Rajan, P. I.; Vijaya, J. J.; Jesudoss, S. K.; Kaviyarasu, K.;
Kennedy, L. J.; Jothiramalingam, R.; Al-Lohedan, H. A.; Vaali-
Mohammed, M.-A. Green-fuel-mediated synthesis of self-assembled
NiO nano-sticks for dual applications�photocatalytic activity on Rose
Bengal dye and antimicrobial action on bacterial strains. Materials
Research Express 2017, 4, No. 085030.

U https://doi.org/10.1021/acsomega.4c07743
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