INORGANIC

CHEMISTRY
ASSIGNMENT

SUBMITTED TO: PROF. RIZWAN SARWAR

SUBMITTED BY : GROUP NO :01

CLASS: BS CHEMISTRY 6TH SEMESTER (M)

TOPIC:Pd-Based Homogenous ElectrocatalystFor

CO2 Reduction
LITERATURE REVIEW 2011-2023
Roll Student Name
Number
1002 Ghulam Fatima
1003 Maryam Munawar
1005 Fatima Sabir
1006 Marriam Khalid
1007 UmmeRuqaiya
1008 Laiba
1009 MisbahFayyaz
1011 MuqasadSaleem
1012 Samra Allah Yar

1013 MahamAnjum

GROUP MEMBERS
2011

Zhe Gao,Yingjun Feng

A super paramagnetic solid catalyst has been successfully synthesized by loading palladium
nanoparticles into the pore network of a mesoporous NiFe2O4 support (Pd/NF300), which was
second-hand as a magnetically separable and highly active catalyst for Suzuki and Heck C–C
coupling reactions. Various techniques were employed to typify the synthesized
NiFe2O4 supports and Pd-loaded catalysts. The Pd/NF300 catalyst showed towering
movement for both Suzuki and Heck reactions even under a very low Pd using amount
(0.08 mol% Pd based on aryl halide). Moreover, the catalyst could be magnetically divided
recycled, and showed a very slight reduction in catalytic activity after five cycles. A
synergetic catalytic effect between the well dispersed Pd 0 and the essential mesoporous
structure of magnetic supports has been proposed to understand its greatly superior catalytic
activities.

References:
Pd-loaded superparamagnetic mesoporous NiFe2O4 as a highly active and magnetically
separable catalyst for Suzuki and Heck reactions
.https://www.sciencedirect.com/science/article/abs/pii/S1381116910005297

2012
Author Information:

This work is supported by university ofHampshire (X.T, Wenxin Du, Kayla E Mackenzie,
D.M
In 2012, While studying a series of carbon supported homogeneous Pd-Sn binary alloyed
catalysts prepared through a modified polyol method as anode electrocatalyst for diect
ethanol fuel cell reactions, in alkaline medium. Transmission electron microscope, energy-
dispersive X rays spectroscopy, X-ray diffraction and aberrstion-corrected scanning
transmission electron microscopy equipped with electron energy loss spectroscopy were used
to characterize the Pd-Sn/C catalysts, where homogeneous Pd-Sn alloys were determined to
be present with the surface of Sn being partially oxidized. Among various Pd-Sn catalysts
Pd86 Sn14/C showed much enhanced current densities in cyclic voltammetric and
chronoamperometricmeasurments, compared to commercial Pd/C. Density functional theory
calculations also confirmed Pd/Sn alloy would result in lower reaction energies for the
dehydrogenation of ethanol, compared to pure Pd crystals. The cyclic voltammetry (CV) of
Pd-Sn and commercial Pd/C (JM) catalysts was first investigated in 0.5 M KOH aqueous
solution All Pd-Sn/C catalysts appear to have similar columbic features compared to Pd/C
such as reduction of Pd oxide, and absorption and desorption of hydrogen. We successfully
made a series of carbon supported Pd-Sn nanoparticles via polyol method, By this we are able
to Identify the homogeneous alloy formation between Pd and Sn with the surface of Sn being
slightly oxidized in Pd86 Sn14/ C electrocatalyststhrough Characterization techniques.

Reference
 Palladium- Tin Alloyed Catalysts for Ethanol Oxidation Reaction In a Alkaline Medium
https://pubs.acs.org/doi/abs/10.1021/cs2005955
2013 (1)

In 2013, Fuchun Zhu and his co-workers investigated methanol, ethanol and formic acid
electro-oxidation by Pd- based catalyst. In this way, high activity of carbon nanotubes are
synthesized using different molar ratios of Pd catalyst i.ePd, PdCu with molar ratio of (1:1),
PdSn with molar ratio of (1:1) and the last catalyst is PdCuSn of molar ratio (1:1:1). This
catalysts can better work using a reducing agent i.e NaBH4. This whole procedure can be
done through chemical reduction. By the process of potential cycling activation, there are the
chances that the additive Cu could be leached, but the dissolution of Sn content in these
catalysts may or may not occur. When we go through several electrochemical proceedings,
we have seen that the catalytic activity for these multi walled carbon nanotubes could be
enhanced when Of based catalyst are homogenised with Cu and SN by making alloys. While
the catalytic activity can’tbe enhanced by using different binary and mono components of of
based catalyst i e PdCu/CNTs, PdSn/SnTs, and Pd/CNTs catalysts respectively. Different
techniques such as X-rays diffraction, chronoamperonetry, X rays photoelectron spectroscopy
and cyclic voltammetry are used for the characterization of these different Pd based catalysts.
The promotion of electrolytic activity can also be analysed though these Pd based catalysts i.e
the Sn and Cu present in these catalysts. The mass activity for methanol is 395.94, for
ethanol is 872.70 and for formic acid electro-oxidation is 534.83 mA mg-1 of Pd. So, it can
be concluded that PdCuSn/CnTs shows good mass activity for electro-oxidation.

Reference

High activity of carbon nanotubes supported binary and ternary Pd-based catalysts for
methanol, ethanol and formic acid electro-oxidation

.https://www.sciencedirect.com/science/article/abs/pii/S037877531300935X

2013 (2)

The one pot water based synthesis using Pt-Pd alloy (Pt-Pd ANFs) are synthesized by the
process of chemical reduction in an aqueous solution of poly allylamine hydrochloride
(PAH). Transmission electron microscopy, selected area diffraction,energy dispersive
spectrum,nitrogen adsorption desorption isotherms, X rays diffraction and X rays
photoelectron spectroscopy are the techniques through which the structure, form, constituents
of Pt-Pd ANFs are characterized. These techniques reveal that the structure of Pt-Pd alloy i.e
Pt-Pd ANFs is highly porous and supported. FTIR describes that the relealibility and
occuranceof PAH and the fast upbringing of crystal nuclei is very crucial for the making of
Pt-Pd ANFs. So, as a whole, these techniques describes the formation mechanism of Pt-
PdANFs.By taking 0.1 M solution of HClO4 in a rotating disk electrode volumetry , the
stability and electrocatalytic growing of Pt-Pd ANFs is measured which can be used for
oxygen reduction reactions. The electrolytic measurements using electrochemical series
reveals that the Pt-Pd ANFs shows a very high range of oxygen reduction reactions.Asa result
a satisfactory result is obtained and the tolerant ability of methanol is enhanced in acidic

conditions. So, the Pt-Pd ANFs Alloys are excellent electrocatalyst which increases its scope
in future.

Reference

Pot Water-Based Synthesis of Pt–Pd Alloy Nanoflowers and Their Superior Electrocatalytic
Activity for the Oxygen Reduction Reaction and Remarkable Methanol-Tolerant Ability in
Acid Media https://pubs.acs.org/doi/10.1021/jp400502y

2013 (3)

The Au@Pd /graphene structures are made from Pd and Au ions using ascorbic acid as a
reducing agent by the process of chemical reduction. The main advantage of Au@Pd/
graphene sheets is that it is bimetallic and surfactant free. Graphene sheets are fabricated on
the Au@Pd core at the size of about 7nm. Different techniques such as X rays diffraction,
mapping analysis (HAADF-STEM) are used for analysing the composition,morhology and
structure of these core. These catalysts such as Au@Pd/graphene are very useful for ethanol

oxidation by electrochemical measurements. The better result can be obtained if we have

small Au core fabricated with thin Pd shells, the value obtained is 11.6mg-1 for better
analysis.

Reference

One-pot synthesis of Au@Pd/graphene nanostructures: electrocatalytic ethanoloxidation for direct

alcoholfuel cells (DAFCs)†
https://pubs.rsc.org/en/content/articlelanding/2013/ra/c3ra40505b
2013(4)

In organic synthesis, these homogenous catalyzed hydroformylation reactions are very useful
for the making or C-C bond. The IrPt,Pd and Fe catalysts are used for the making of broadly
used aldehydes through the conversion of inexpensive chemical materials. In market, these
aldehydes (product) is in demand for the removal of pest, used in household(detergents)
prepared on a million ton scale. These product can also be used for the preparation of
medicines in pharmaceutical industries. Previously, the hydroformylation reactions occurred
through rhodium based catalysts. But this metal is very expensive, so of based homogenous
electrocatalyst is used for hydroformylation reactions for the synthesis of alkynes, alkenes
and aldehydes.

Reference:

Alternative Metals for Homogeneous Catalyzed Hydroformylation

Reactionshttps://onlinelibrary.wiley.com/doi/10.1002/anie.201208330

2014 (1)

A proficient palladium-catalyzed hilter kilter hydrogenation of an assortment of unprotected

indoles has been fostered that surrenders to 98% ee utilizing major areas of strength for a
corrosive as the activator. This technique was applied in the easy blend of naturally dynamic
items containing a chiral indoline skeleton. The system of Pd-catalyzed uneven
hydrogenation was researched also. Isotope-marking responses furthermore, ESI-HRMS
demonstrated that an iminium salt framed by protonation of the C C obligation of indoles
was the critical middle in this response. The significant proposed dynamic synergist Pd−H
species was seen with 1H NMR spectroscopy. It was foundthat proton trade between the
Pd−H dynamic species and dissolvable trifluoroethanol (TFE) didn't happen, albeit this
protontrade had been recently seen between metal hydrides and alcoholic solvents. Thickness
utilitarian hypothesis estimationswere additionally done to give further understanding into the
component of Pd-catalyzed unbalanced hydrogenation of indoles.

Thismix of trial and hypothetical examinations recommends that Pd-catalyzed hydrogenation

goes through a stepwise outersphere and ionic hydrogenation system. The initiation of
hydrogen gas is a heterolytic interaction helped by trifluoroacetate of Pd complex through a
six-membered-ring change state. The response continues well in polar dissolvable TFE
attributable to its capacity to settle the ionic intermediates in the Pd−H age step. The solid
Brønsted corrosive activator can amazingly diminish the energy boundary for both Pd−H age
and hydrogenation. The high enantioselectivityemerges from a hydrogen-holding connection
between N−H of the iminium salt and oxygen of the planned trifluoroacetate in the eight-
membered-ring progress state for hydride move, while the dynamic chiral Pd complex is a
regular bifunctional impetus, affecting both the hydrogenation and hydrogen-holding
collaboration between the iminium salt and the organized trifluoroacetate of
Pdcomplex.Remarkably, the Pd-catalyzed uneven hydrogenation is moderately lenient to
oxygen, corrosive, and water.
Reference:

Homogenous Pd-Catalyzed Asymmetric Hydrogenation of Unprotected Indoles: Scope and

Mechanistic Studies https://pubs.acs.org/doi/abs/10.1021/ja502020b

2014 (2)

In 2014, Qin Shi,a Hui Wang,aShaoleiLiua and ZhaoyongBian investigated that Palladium-
modified graphene gas-diffusion cathodes were prepared using Pd/graphene catalysts and
characterized using cyclic voltammetry, scanning electron microscopy, transmission electron
microscopy, X-ray diffraction, Raman spectroscopy and Fourier transform infrared
spectrometryPd particles were amorphous, with an average size of 5.4 nm, and were widely
spread throughout graphene. When the Pd/graphene gas-diffusion cathode was fed hydrogen,
reductive dechlorination of 2,4-DCP occurred, whereas two-electron reduction of O2 to
H2O2 was accelerated in air.
Reference :

Electrocatalytic degradation of 2,4-dichlorophenol using a Pd/graphene gas-diffusion electrode

https://pubs.rsc.org/en/content/articlehtml/2014/ra/c4ra09253h

2015 (1)

Ruud Kortlever, Collin Balemans, Youngkook Kwon, Marc T.M. Koper

Current interest in the electrochemical reduction of CO2 as a potential energy storage process
is high. In this study, we demonstrate that the onset potential for the conversion of CO2 to
formic acid on electrodeposited palladium on platinum, a suitable formic acid oxidation
catalyst, is significantly lower than on bulk palladium. One reaction pathway at low
overpotential produces formic acid either directly from the reduction of bicarbonate or from
the reduction of CO2 generated from bicarbonate near the surface, and the other reaction
pathway at more negative potentials produces formic acid directly from the reduction of
CO2.Additionally, we demonstrate that the catalyst is capable of reversible formic acid
oxidation and CO2 reduction. Regrettably, the operations are hampered by the catalyst being
poisoned, most likely by CO.
Reference
Electrochemical CO2 reduction to formic acid on a Pd-based formic acid oxidation catalyst
https://www.sciencedirect.com/science/article/abs/pii/S0920586114005537
2015 (2)

Jeffrey A. TherrienMichael O. Wolf*, and Brian O. Patrick

To learn how these polyannulated NHCs affect the ability of the complexes to
electrochemically reduce CO2 to CO in the presence of 2,2,2-trifluoroacetic acid and 2,2,2-
trifluoroethanol as proton sources, phenanthro- and pyreno-annulated N-heterocyclic
carbenes (NHCs) have been added. The annulated phenanthrene and pyrene moieties are
demonstrated to be extra sites for redox activity in the pincer ligand, enabling greater electron
donation. These complexes are examined for their ability to decrease CO2 and predicted
using calculations based on density functional theory. The chemical relevance of redox
events for complexes of this sort, as well as the significance of anion binding and
dissociation, are studied using electrochemical and computational methods.
Reference

PolyannulatedBis(N-heterocyclic carbene)palladium Pincer Complexes for Electrocatalytic

CO2 Reduction https://pubs.acs.org/doi/10.1021/acs.inorgchem.5b01698

2016

A. Lazzarini , A. Piovano , R. Pellegrini, G. Leofanti , G. Agostini M. R. Chierotti , R.

Gobetto, A. Battiato , G. Spoto, A. Zecchina , C. Lamberti and E. Groppo

Widely employed as supports for industrial catalysts based on metal nanoparticles are
activated carbons. The carbon activation process has a significant impact on the catalytic
performance of catalysts that are supported on carbon. Despite its crucial role, the impact
caused by various activation techniques has only seldom been thoroughly studied. This
research focuses on two wood-derived carbons that have been either activated by steam or
phosphoric acid and the matching catalysts made of supported Pd nanoparticles. We show
that, while the palladium dispersion remains the same, the performance of the catalysts in
hydrogenation processes varies depending on the type of carbon utilised as a carrier. To
properly characterise carbons and catalysts at the micro- and nanoscale, we suggest a multi-
technique approach. We focus on determining how the activation process affects the surface
properties of carbons and the related catalysts, including texture (as determined by N2
physisorption), morphology (as determined by scanning electron microscopy), structure (as
determined by solid state nuclear magnetic resonance, Raman spectroscopy, and X-ray
diffraction), and surface property. The thorough characterization method put forward in this
work enables, at least in part, the rationalisation of the function of activated carbons in
attracting the performance of a hydrogenation catalyst.

Catalytic performance of Pd/CW(F) and Pd/CChemi(F) catalysts in the hydrogenation of

resorcinol with formate. Reaction conditions: T = 40–55 °C, 5 wt% catalyst loading. D (%)
indicates the palladium dispersion as evaluated by the CO chemisorption method. Selectivity
value is referred at 18 h
Conversion (%)
Catalyst D (%) 2 h 3h 18 h Selectivity (%)
Pd/CW(F) 28.1 30.8 40.2 96.2 98.82
Pd/CChemi(F) 26.3 29.4 38.1 96.8 85.16

Table 2 Catalytic performance of Pd/CW and Pd/CChemi catalysts in the debenzylation of N-

benzyl-N-ethylaniline to give N-ethylaniline and toluene. Reaction conditions: T = 65 °C, P =
3 bar, 3 wt% catalyst loading. D (%) indicates the palladium dispersion as evaluated by the
CO chemisorption method
Catalyst D (%) Activity (mmolH2min−1 gcat−1)
Pd/CW 23.5 14.6
Pd/CChemi 18.8 31.1

Chart 1
The unreduced Pd/CW and Pd/CChemi catalysts were tested in the debenzylation of N-
benzyl-N-ethylaniline to give N-ethylaniline and toluene (Chart 2 and Table 2). Also in this
case the metal dispersion is quite similar for the two catalysts, but Pd/C Chemi is much more
active than Pd/CW.
Chart 2

References

A comprehensive approach to investigate the structural and surface properties of activated carbons
and related Pd-based catalystshttps://pubs.rsc.org/en/content/articlehtml/2016/cy/c6cy00159a

2017(1):

Sichao Ma, Masaaki SadakiyoMinakoHeimaRaymondLuoRichard T. HaaschJake I.

GoldMiho Yamauchi and Paul J. A. Kenis

The potential for using CO2 as a carbon feedstock and for storing intermittent renewable
energy is demonstrated via electrochemical conversion of CO2. Cu is the only metallic
electrocatalyst now known to convert CO2 to significant amounts of hydrocarbons, but a
variety of other products, including CO, HCOO-, and H2, are frequently produced as well.
Better catalysts are required, particularly those with excellent selectivity for certain products
and high activity. In order to identify the critical element required to achieve high selectivity
for C1 or C2 chemicals in CO2 reduction, a variety of bimetallic Cu-Pd catalysts with
ordered, disordered, and phase-separated atomic arrangements (Cuat:Pdat = 1:1) as well as
two additional disordered arrangements (Cu3Pd and CuPd with Cuat:Pdat = 3:1 and 1:3) are
studied in this study. The ordered CuPd catalyst showed the highest selectivity for C1
products (>80%) when compared to the disordered and phase-separated CuPd catalysts. In
comparison to CuPd3 and ordered CuPd, phase-separated CuPd and Cu3Pd exhibit better
selectivity (>60%) for C2 compounds, which may indicate that surfaces with nearby Cu
atoms are more likely to dimerize C1 intermediates. Geometrical influences rather than
electrical effects appear to be crucial in controlling the selectivity of bimetallic Cu-Pd
catalysts, according to surface valence band spectra. These findings suggest that geometric
layouts can be used to adjust selectivities to various products. This knowledge could be used
to improve the activity and selectivity of CO2 reduction by designing catalytic surfaces.
References:

Electroreduction of Carbon Dioxide to Hydrocarbons Using Bimetallic Cu–Pd Catalysts with

Different Mixing Patterns. https://pubs.acs.org/doi/abs/10.1021/jacs.6b10740

2017(02)

Anna Monfredini, Veronica Santacroce, Luciano Marchiò, Raimondo Maggi, Franca

Bigi, Giovanni Maestri, and Max Malacria

A specific family of discrete trinuclear complexes that are the transition-metal equivalents of
carbon-based aromatics can be stabilised by appropriately delocalized metal-metal bonds.
The development of a useful catalytic technique for the semireduction of internal alkynes
under transfer hydrogenation conditions has been influenced by this chemical stability. No
additional solvent is needed for the reaction, and a straightforward workup yields pure
results. This combines with full cis-selectivity, wide functional group acceptance, and
catalytic charges as low as 100 ppm on multigram scale.

References:

Semi-Reduction of Internal Alkynes with Prototypical Subnanometric Metal Surfaces:

Bridging Homogeneous Catalysis with Trinuclear All-Metal
Aromatics.thttps://pubs.acs.org/doi/full/10.1021/acssuschemeng.7b01847

2018(01)
Emile E DeLuca, Zhen Xu, Jasper Lam, Michael O Wolf
Stabilizing interactions between charged electrocatalytic intermediates and a series of
cationic residues were explored through the synthesis and characterization of six palladium
bis(N-heterocyclic carbene) (NHC) complexes bearing unique onium functionalities. The
presence of a positively charged, pendant substituent was found to mediate electrode kinetics
and facilitate CO2 coordination to the catalytic center in a systematic fashion. The
introduction of cationic moieties into this system is shown to enhance catalytic selectivity for
the conversion of CO2 to CO by as much as 5 times that of an alkyl-bearing analog. A
combination of electrochemical experiments and computational analysis demonstrates that
catalyst performance benefits most from a bulky onium unit tethered to the catalyst through a
flexible linker. This behavior was interpreted as a preference for a wide, hydrophobic
reaction pocket that allows for the unhindered formation of catalytic intermediates and
mediated interaction with the solution.
Reference :

Improved Electrocatalytic CO2 Reduction with Palladium bis(NHC) Pincer Complexes

Bearing Cationic Side
Chains .https://scholar.google.com.pk/scholar_url?url=https://pubs.acs.org/doi/abs/10.1021/
acs.organomet.8b00649&hl=en&sa=X&ei=Ev-
XZIPCEbqJy9YP2bSe4Ac&scisig=AGlGAw-ne4Xu6xfaZO8eL6o9ytsY&oi=scholarr

2018(02)

DunfengGao, Hu Zhou, Fan Cai, Jianguo Wang, Guoxiong Wang, XinheBao

The electrochemical CO2 reduction reaction (CO2RR), with water as a hydrogen source, has
been attracting great attention due to its promising applications for carbon recycle utilization
and renewable electricity storage. In order to drive the process economically, highly efficient
catalysts are urgently needed to overcome the constraints of high overpotential, low Faradaic
efficiency, and current density of CO2RR. This Perspective summarizes the performance of
Pd-containing nanostructures toward CO2RR and related reaction mechanisms. The product
selectivity of the Pd catalysts strongly depends on the structure and composition, and the
dynamic evolution of active phases induced by the applied potential and reaction intermediate
of CO2RR. Introducing a second metal can effectively suppress the decay in the catalytic
performance of a Pd catalyst and further improve the activity and selectivity of CO2RR. The
electrochemical promotion of catalysis effect drastically improves the production rate of
formate over Pd nanoparticles, which demonstrates the advantage of the coupled thermo- and
electrocatalytic CO2 reduction. The challenges and tentative strategies for the further
application of Pd-containing catalysts in CO2RR are also discussed.
Reference :Pd-Containing Nanostructures for Electrochemical CO2 Reduction Reaction
https://scholar.google.com/scholar?start=70&q=pd+based+catalysts+
%22electrocatalytic+co2%22&hl=en&as_sdt=0,5#d=gs_qabs&t=1687682572091&u=%23p
%3D3ug0pbBreb8J

2018(03)

RamyakrishnaPothu a, Harisekhar Mitta b, Prasun Banerjee c, RajenderBoddula d, Rajesh K.

Srivastava e, Pramod K. Kalambate f g, Ramachandra Naik h, Ahmed BahgatRadwan d,
Noora Al-Qahtani d 2018.

One of the most significant industrial processes is the catalytic methanol synthesis from
carbon dioxide because methanol is a future energy carrier for producing fuels and high-
value-added commodities, the so-called “methanol economy” is carbon neutral. As a solution
to climate change, the widespread belief that carbon dioxide can be recycled by
hydrogenation into methanol has motivated the development of more efficient and selective
catalysts. Efficient 2 wt% Pd/CeO2 catalysts for thermochemical CO2 hydrogenation have
recently been investigated. However, the rationale behind the low Pd loading (2 wt%) in
CeO2 needs to be clarified, and comprehensive research into Pd tuning is lacking. In this
article, we describe the synthesis of various palladium contents (0.5, 1, 2, 4, and 6 wt%)
supported on ceria nanorods (Pd/CeO2) for selective hydrogenation of CO2 to methanol
under vapor-phase. The impact of Pd on the physicochemical properties of CeO2 was
examined using various characterization techniques. The enhanced catalytic activity was
caused by the 2 wt% Pd/CeO2 catalyst's most significant level of metallic Pd species, strong
interactions between Pd and CeO2, uniform Pd dispersion on CeO2, increased reducibility,
oxygen mobility, and weak basic sites. This study reveals that changing the percentage of
metal in the catalyst supports a valuable technique for designing efficient oxides-supported
metal-based catalysts for CO2 conversions.
Reference :Insights into the influence of Pd loading on CeO2 catalysts for CO2 hydrogenation
to methanol

https://www.sciencedirect.com/science/article/pii/S258929912300023X

2018(04)

Kohsuke Mori, Taiki Sano, Hisayoshi Kobayashi, and Hiromi Yamashita

Cite this: J. Am. Chem. Soc. 2018, 140, 28, 8902–8909

Publication Date:June 22, 2018

The hydrogenation of carbon dioxide (CO2) to formic acid (FA; HCOOH), a renewable
hydrogen storage material, is a promising means of realizing an economical CO2-mediated
hydrogen energy cycle. The development of reliable heterogeneous catalysts is an urgent yet
challenging task associated with such systems, although precise catalytic site design protocols
are still lacking. In the present study, we demonstrate that PdAg alloy nanoparticles (NPs)
supported on TiO2 promote the efficient selective hydrogenation of CO2 to give FA even
under mild reaction conditions (2.0 MPa, 100 °C). Specimens made using surface
engineering with atomic precision reveal a strong correlation between increased catalytic
activity and decreased electron density of active Pd atoms resulting from a synergistic effect
of alloying with Ag atoms. The isolated and electronically promoted surface-exposed Pd
atoms in Pd@Ag alloy NPs exhibit a maximum turnover number of 14 839 based on the
quantity of surface Pd atoms, which represents a more than 10-fold increase compared to the
activity of monometallic Pd/TiO2. Kinetic and density functional theory (DFT) calculations
show that the attack on the C atom in HCO3– by a dissociated H atom over an active Pd site
is the rate-determining step during this reaction, and this step is boosted by PdAg alloy NPs
having a low Pd/Ag ratio.

Reference :

Surface Engineering of a Supported PdAg Catalyst for Hydrogenation of CO2 to Formic

Acid: Elucidating the Active Pd Atoms in Alloy Nanoparticles
https://pubs.acs.org/doi/10.1021/jacs.8b04852

2018(05):
Bei Jiang, Xia-Guang Zhang, Kun Jiang, De-Yin Wu, Wen-Bin Cai 2018
Facile interconversion between CO₂ and formate/formic acid (FA) is of broad interest in
energy storage and conversion and neutral carbon emission. Historically, electrochemical
CO₂ reduction reaction to formate on Pd surfaces was limited to a narrow potential range
positive of −0.25 V (vs RHE). Herein, a boron-doped Pd catalyst (Pd–B/C), with a high CO
tolerance to facilitate dehydrogenation of FA/formate to CO ₂, is initially explored for
electrochemical CO₂ reduction over the potential range of −0.2 V to −1.0 V (vs RHE), with
reference to Pd/C. The experimental results demonstrate that the faradaic efficiency for
formate (ηHCOO–) reaches ca. 70% over 2 h of electrolysis in CO ₂-saturated 0.1 M KHCO ₃
at −0.5 V (vs RHE) on Pd–B/C, that is ca. 12 times as high as that on homemade or
commercial Pd/C, leading to a formate concentration of ca. 234 mM mg–¹ Pd, or ca. 18 times
as high as that on Pd/C, without optimization of the catalyst layer and the electrolyte.
Furthermore, the competitive selectivity ηHCOO–/ηCO on Pd–B/C is always significantly
higher than that on Pd/C despite a decreases of ηHCOO– and an increases of the CO faradaic
efficiency (ηCO) at potentials negative of −0.5 V. The density functional theory (DFT)
calculations on energetic aspects of CO₂ reduction reaction on modeled Pd(111) surfaces
with and without H-adsorbate reveal that the B-doping in the Pd subsurface favors the
formation of the adsorbed HCOO*, an intermediate for the FA pathway, more than that of
*COOH, an intermediate for the CO pathway. The present study confers Pd–B/C a unique
dual functional catalyst for the HCOOH ↔ CO₂ interconversion.

Reference:

Boosting Formate Production in Electrocatalytic CO2 Reduction over Wide Potential

Window on Pd Surfaces

https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=pd+based+catalysts+
%22electrocatalytic+co2%22&oq=#d=gs_qabs&t=1687682405134&u=%23p
%3DNX8vKF95l6IJ

2018(06)

Nichoas A DeLucia, Nivedita Das, Sean Overa, Avishek Paul, Aaron K Vannucci

Catalysis Today 302, 146-150, 2018

The molecular, homogeneous catalysts [Pd(tpy)Cl]Cl and [Ni(tpy)](PF6)2, where tpy is

2,2′:6′,2′′- terpyridine, have been utilized to perform selective hydrodeoxygenation of benzyl
alcohol, benzaldehyde, and benzophenone under very mild conditions. The [Pd(tpy)Cl]Cl
catalyst exhibits excellent catalytic activity, with the complete selectivity towards
hydrodeoxygenation, even at room temperature. Results indicate that the single-site nature of
the molecular catalysts is what leads to the complete selectivity and the absence of aromatic
ring hydrogenation products. A two-step mechanism consisting of H2 activation by the
catalyst to form a metal hydride complex, followed by selective hydrodeoxygenation is
proposed. These results illustrate the possible advantages for the use of homogeneous
catalysts in the conversion of lignin biomass to fuel or chemical feedstocks.

Reference:

Low temperature selective hydro deoxygenation of model lignin monomers from a

homogeneous palladium catalyst

https://www.sciencedirect.com/science/article/abs/pii/S0920586117303619

2018(07):

CihangirBoztepe, AsimKünkül, SedatYaşar, NevinGürbüz

New generation, novel, environmentally safe polymeric heterogeneous catalysts which

included catalytically active NHC-Pd-pyridine complexes were prepared by radical
polymerization of NHC-Pd-pyridine complexes with Acrylamide (AAm) and 2-acrylamido-2-
methylpropane sulfonic acid (AMPS) monomers in the presence of N,N′-
methylenebisacrylamide (MBA) cross-linked. Structural characterization of NHC-Pd-pyridine
complexes was conducted by using NMR, FT-IR while the structural characterization of cross
linked polymeric catalyst systems.

Reference :Hydrogenization of homogeneous NHC-Pd-pyridine catalysts and investigation

of their catalytic activities in Suzuki-Miyaura coupling reactions

https://www.academia.edu/40943072/
Heterogenization_of_homogeneous_NHC_Pd_pyridine_catalysts_and_investigation_of_their
_catalytic_activities_in_Suzuki_Miyaura_coupling_reactions

2018(08):HojatVeisi, SepidehNajafi, Saba Hemmati

This article is devoted to synthesis of a new magnetic interphase palladium catalyst that has
been immobilized on chitosan-biguanidine coated-magnetic Fe3O4 nanoparticles
[Pd(0/II)/CS-bigua@Fe3O4]. Such surface functionalization of magnetic particles is a
promising method to bridge the gap between heterogeneous and homogeneous catalysis
approaches. The structure, morphology, and physicochemical properties of the particles were
characterized through different analytical techniques, including Fourier transformed infrared
spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), transmission
electron microscopy (TEM), vibrating sample magnetometer (VSM), wavelength-dispersive
X-ray spectroscopy (WDX), inductively coupled plasma (ICP), energy dispersive X-ray

spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). Pd(0/II)/CS-

bigua@Fe3O4 demonstrated high catalytic activity as a recyclable nanocatalyst toward
Suzuki-Miyaura cross-coupling reactions, at room temperature. Furthermore, the catalyst
could be recovered and reused several times with no significant palladium leaching or change
in its activity.

Reference:
Pd (II)/Pd (0) anchored to magnetic nanoparticles (Fe3O4) modified with biguanidine-
chitosan polymer as a novel Nano catalyst for Suzuki-Miyaura coupling reactions
https://pubmed.ncbi.nlm.nih.gov/29476850/

2019(01):

When employed in the electro-synthesis of valuable chemicals or fuels, carbon dioxide (CO2)
is seen as a useful greenhouse gas that can be trapped. On the other hand, because ethanol is
mostly derived from crops and is seen to be a possible contender for low temperature fuel cell
applications, there is also a lot of interest in its beneficiation. Despite having many positive
attributes, ethanol is dangerous because it is resistant to oxidation. The primary goal of the
project is to create bio-inspired metal oxide-support catalysts that will improve the CO2
reduction, fuel cell performance, and ethanol oxidation activities, eficiencies, and selectivities
of Pd catalysts. Here, pomegranate peel extracts were used as the reducing agent in a green,
simple, one-step approach to support Pd nanoparticles on NiO/C. To demonstrate and
quantify the presence of Pd, Ni, O, and C in the produced sample, a number of
characterizations were conducted. The creation of pure NiO/C and (%5 Pd) Pd-NiO/C with
their major constituent elements, mixed nanostructures, and co-existence of Pd and NiO/C
were successfully prepared, as demonstrated by microscopic methods. The resulting Pd-
NiO/C nanocatalyst showed increased activity for the oxidation of ethanol and showed that it
is more resistant to poising by intermediate oxidation products. Passive circumstances at 1 M
ethanol in 1M KOH led to improved cell performance with current and power densities of 66
mA cm2 and 26 mW cm2 in comparison to commercial Pd/C. The nanocatalyst additionally
demonstrated good selectivity to HCOOH with increased current efficiencies of 45%.

Reference
NiO/C as a Pd support catalyst synthesised in a single step for dual applications: CO2 electro-
reduction and alkaline direct ethanol fuel cells in 2019.https://scholar.google.com/scholar?
hl=en&as_sdt=0%2C5&q=pd+based+homogeneous+electro-
catalyst+for+CO2+reduction+2019&btnG=#d=gs_qabs&t=1687680528153&u=%23p
%3D6WMvku9FLBUJ

2019(02):

Using a pd-based homogeneous electro-catalyst, Jiachang Zeng, Wenbiao Zhang, Yang

Yang, Dan Li, Xiang Yu, and QingshengGao worked on reducing CO2 in 2019. They are
currently looking into the process.To increase transitional attachments and subsequently
increase the activity and selectivity of the CO2 reduction reaction (CO2RR), solid-solution-
alloy electrocatalysts must be built with customizable surface electronic configurations. The
electronic impacts on the CO2RR are explored here using Pd1-xAgx alloy electrocatalysts as
a platform. Among newly reported electrocatalysts, the best Pd0.75Ag0.25/C has a better CO
Faradaic efficiency of 95.3% at 0.6 V (vs RHE) in 0.5 M KHCO3. Additional evidence from
experimental and theoretical research shows that changing the composition of Pd1-xAgx
alloys can effectively change the electronic configurations and, as a result, destroy the
integral mounting connection of the binding energies of various intermediates (*COOH and
*CO). Pd0.75Ag0.25, a member of Pd1-xAgx, gains the clearly weaker *CO and *H bindings
but keeps the binding with *COOH, helping to improve the kinetics towards CO product.
This work will stimulate new design approaches for active and selective electrocatalysts by
elucidating a workable technique to break the scaling connection and better elucidate the
underlying process.

Reference :

Composition Tuning of Pd-Ag Alloy Electrocatalysts for CO2 Reduction to Break the
Scaling Relationship2019 https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=pd-
Ag+alloy+electrocatalysts+fot+CO2+reduction
%3Acomposition+tuning+to+break+scaling+relationship+&btnG=#d=gs_qabs&t=16876808
88818&u=%23p%3D7D2DBY1yLKEJ

2020
In 2020,Yuan Zhou and Bioa Zhang introduced this catalyst.

Renewable fuel like formic acid can be converted in to clean electricity in fuel cells by high-
efficient electrochemical oxidation. The conversion rate is fundamentally direction by the
synergy of interactive aspects like catalytic activity and the accessibility to active sites,
electron transfer, and anti-poisoning stability.And For the first time, for the fuel cells,ordered
mesoporous carbon (OMC) is used as the substrate for Pd–PdO catalyst. The unique ordered
pore-channel network of OMC can increase the spatial dispersion of Pd nanoparticles on the
pore-channel wall, while the hollow pore-channel can facilitate reactant transport. Microwave
and annealing treatments are found to increase the chemical reduction and to strengthen the
anchoring of Pd–PdO catalyst on OMC substrate, respectively. For fuel cell testing, the Pd–
PdO/OMC catalyst is applied to an air-breathing microfluidic fuel cell and achieves a
maximum power density of about 63.0 mW cm−2, at least one-fold higher than that the
similar previous reports.

Reference:

1-High performance formic acid fuel cell benefits from Pd–PdO catalyst supported by
ordered mesoporous carbon.

https://www.sciencedirect.com/science/article/abs/pii/S0360319920327774

2020(02):

NiyaziSerdarSariciftci,AsiaChem Magazine, 2020

We want to bring the idea of conversion of CO2 into synthetic fuels (CO2 recycling) into
attention, as a possible approach for transportable storage of renewable energy. Recycling of
CO2 by homogeneous and catalytic approaches have been investigated with enhancing
emphasis within the scientific community. In the last decades, especially using organic and
bioorganic systems towards CO2 reduction has provided great interest. Chemical,
electrochemical, photoelectrochemical, and bioelectrochemical approaches are discussed
vividly as new routes towards the conversion of CO2 into synthetic fuels and/or useful
chemicals in the previous literature.So here we want to especially emphasize the new
developments in bio-electrocatalysis with some previous examples.

Reference:

-CO2 Recycling: The Conversion of Renewable Energy into Chemical

Fuels .https://scholar.google.com/scholar?
hl=en&as_sdt=0%2C5&q=pd+based+catalyst+for+CO2+reduction....homogeneous+catalyst
+of+year+2020+&btnG=#d=gs_qabs&t=1687682670946&u=%23p%3DniCLbxk0YEkJ

2020(03):

In 2020,LakshamiKantamMannipalli and PrivanLikhar introduced this catalyst.

Carbon carbon coupling reactions are one of the most important system to be studied and the
designs of the palladium based phosphine free catalysts is cruical.In this way we present a
result of the work carried out by our main research group on the design and preparation of
efficient and phosphine free catalyst for Heck and Suzuki coupling reactions of the
deactivated and sterically hundered substrates.

Reference:

-Advances in CC coupling reactions catalyzed by homogenous phosphine free palladium

catalys,https://scholar.google.com/scholar?
hl=en&as_sdt=0%2C5&q=advances+in+CC+coupling+reactions+of+homogenous+catalyst+
phosphine+free+palladium+based+catalyst+&btnG=#d=gs_qabs&t=1687682953255&u=
%23p%3DMI7kTY9vfbcJ

2021 (1) :

In 2021, Soumalya Sinha and Liviu M. Mirica* investigated the characteristics of palladium
based catalyst i.e [(t BuN4)PdIIIMeCl]+. The
development of electrocatalysts for selective O2-
to-H2O conversion, known as the O2 reduction
reaction (ORR), is of tremendous importance for enhancing fuel cell performance.They
described the synthesis and characterization of a number of organometallic PdIII complexes
stabilised by the tetradentate ligand N,N′-di-tert-butyl-2,11-diaza[3.3](2,6)pyridinophane (t
BuN4). Analyses of electrochemical data indicate the development of a binuclear PdIII
intermediate in solution, most likely a PdIII-peroxo-PdIII species, which governs the
thermochemistry of the ORR process for [(t BuN4)PdIIIMeCl]+ in MeCN, making it a rare
example of a bimolecular ORR process.The maximum second-order turnover frequency
TOFmax(2) = 2.76ൈ108 M–1 sec–1 was determined for 0.32 mM of [(t BuN4)PdIIIMeCl]
+ in the presence of 1 M AcOH in O2-saturated MeCN with an overpotential of 0.32 V. By
comparison, a comparatively lower TOFmax(2) = 1.25ൈ105 M–1 sec–1 at a higher
overpotential of 0.8 V was observed for [(t BuN4)PdIIIMeCl]PF6 adsorbed onto EPG
electrodes in O2-saturated 1 M H2SO4 aqueous solution. Overall, a complete ORR reactivity
investigation using a new PdIII organometallic complex and benchmarking its selectivity and
energetics towards O2 reduction in MeCN and acidic aqueous solutions is given herein..

Reference :

Electrocatalytic O2 Reduction by an Organometallic Pd(III) Complex via a Binuclear Pd(III)

Intermediate https://sg.docworkspace.com/l/sIKbJ6vGOAf-U4KQG?sa=e1&st=0t

2022(01):

To advance the use of metal catalysts in clean energy technologies, a precise understanding
of interfacial metalhydrogen interactions is essential, especially under in operando
circumstances. The interaction of Pd with hydrogen during active electrochemical processes
is complex, different from that of most other metals, and has not yet been fully understood,
despite the fact that Pd-based catalysts are frequently used for electrochemical hydrogen
generation and hydrogenation. In this study, the competitive relationship between
electrochemical carbon dioxide reduction (CO2RR) and hydrogen sorption kinetics is
examined, as well as the hydrogen surface adsorption and sub-surface absorption (phase
transition) characteristics of Pd and its alloy nanocatalysts under operando electrocatalytic
conditions. The key effects of the local electrolyte environment, such as proton donors with
different PKA on the hydrogen sorption kinetics during CO2RR, are revealed through
systematic dynamic and steady-state evaluations, which provide additional insights into the
electrochemical interfaces and enable the catalytic systems to be optimised.
Reference:

Critical role of hydrogen sorption kinetics in electrocatalytic CO 2 reduction revealed by on-

chip in situ transport investigation https://www.nature.com/articles/s41467-022-34685-9

2023(01):

SagnikChakrabarti, Toby J. Woods, and Liviu M. Mirica* Department of Chemistry, University

of Illinois at Urbana-Champaign, Urbana, Illinois,

Herein we report the synthesis, characterization, and electrocatalytic CO2 reduction activity
of a series of PdII complexes supported by tetradentatepyridinophane ligands. particularly,
we focus on the electrocatalytic CO2 reduction activity of a PdII complex supported by the
mixed hard/soft 2,11-dithia[3.3](2,6)pyridinophane (N2S2) ligand . This is one of the few
examples of a Pd complexes supported by a mixed hard-soft ligand which selectively
produces CO from the electrocatalytic reduction of CO2. Notably, unlike previously reported
molecular Pd complexes, selective CO2RR occurs in presence of weak proton sources such
as 2, 2, 2 trifluoroethanol (TFE) and phenol, at mild overpotentials (~160 mV) and with high
rates (kobs = 4.5 x 103 s-1, with phenol as proton source) and at Faradaic efficiencies of up to
70% for CO, without any H2 being detected. 2 As the catalyst was not stable to long term
electrolysis, we analyzed possible decomposition routes for this catalyst and, based on the
characterization of its reaction with CO by UV-vis, NMR, and IR spectroscopy, we propose
the intermediacy of a binuclear [(N2S2)PdI (η2 -CO)]2 species toward the ultimate
decomposition of the catalyst into free ligand and Pd0 . Overall, these studies offer important
insights into Pd catalyst decomposition and may explain the historically poor performance of
related Pd molecular catalysts for CO2 reduction. In addition, the structurallyrelated hard N-
donor diazapyridinophane (RN4)Pd complexes are shown.

REFERENCES :

Insights into the Mechanism of CO2 Electroreduction by Molecular Palladium-Pyridinophane

Complexes https://scholar.google.com/scholar?
hl=en&as_sdt=0%2C5&q=Insights+into+the+Mechanism+of+CO2+Electroreduction+
+by+Molecular+Palladium-Pyridinophane+Complexes&btnG=