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org/acscatalysis Letter

Tandem Catalysis of Direct CO2 Hydrogenation to Higher Alcohols

Di Xu, Hengquan Yang, Xinlin Hong,* Guoliang Liu,* and Shik Chi Edman Tsang
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ABSTRACT: Direct CO2 hydrogenation to higher alcohols (HA) is highly attractive but remains a
huge challenge due to the low HA productivity. Herein we develop a highly active multifunctional
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catalyst composed of CuZnAl and K-CuMgZnFe oxides which significantly improve the HA space time
yield (STY) to 106.5 mg gcat−1 h−1 (2.24 mmol gcat−1 h−1) with more than 90% of the HA fraction in
total alcohol products. A strong synergistic effect occurs when these two components are in proper
proximity and at an appropriate mass ratio, which can efficiently facilitate the conversion of CO2 to HA
by promoting the formation of a *CO intermediate via the reverse water gas shift reaction over CuZnAl
and subsequently the *CO migration and conversion on K-CuMgZnFe.
KEYWORDS: higher alcohols, CO2 hydrogenation, multifunctional catalyst, synergistic effect, proximity effect

H igher alcohols (HA) are a group of attractive chemicals

due to their widespread applications as solvents, fuel
additives, and daily chemicals.1 However, HA production
deep understanding toward the reaction mechanism was still
scarce. Herein, we successfully developed a highly active
multifunctional catalyst composed of commercial CuZnAl
heavily relies on the fermentation of sugar and hydration of oxides donated as CZA and self-synthesized K-CuMgZnFe
petroleum-derived alkene which aggravate the burden of grain oxides named as K-CMZF, for CO2 hydrogenation to HA. The
and nonrenewable resources.2 As an abundant and renewable powder mixing configuration with a mass ratio of 1:1 was
carbon source, directly converting CO2 into valuable HA is screened out for the best HAS activity (106.5 mg gcat−1 h−1)
fascinating.3 Typically, Rh-based,4 Co-based,5 Cu-based,6 and with enhanced CO2 conversion (42.3%). From this work, we
Mo-based catalysts7 are applied in higher alcohol synthesis demonstrate that the strong synergetic effect and the
(HAS) from CO2 hydrogenation. Although much progress has appropriate proximity of these two components significantly
been made in recent years, the CO2-to-HA reaction still suffers accelerate the HAS rate by promoting the migration of the
from low HA productivity. *CO intermediate.
The CO2-to-HA conversion requires a coupling between the We first compared the catalytic performance of a series of
transformation of CO2 to reactive C1 species (e.g., *CO, multifunctional catalysts with different CZA/K-CMZF mass
*HCOO, *CH3O, and *CHx) and subsequent C−C bond ratios at 5 MPa, 320 °C, and 6 L gcat−1 h−1. As shown in Table
formation reactions.4−6 The thermodynamic stability and 1 and Figure S1, the sole CZA catalyst shows high reverse
chemical inertness of CO2 molecules often lead to low water gas shift reaction (rWGSR) activity with CO selectivity
conversion of CO2 in hydrogenation reactions. Moreover, the of 90.9% at a CO2 conversion of 26.8%. No CH4 and C2+
reaction rate of C−C coupling would be severely restricted by products were detected, suggesting the poor CO dissociation
the low coverage of reactive C1 species on the surface of the ability of the CZA component. By contrast, the sole K-CMZF
catalyst due to the low CO2 conversion. Very recently, great catalyst exhibits a CO2 conversion of 30.4%, yet with an HA
breakthroughs have been made in C1 catalytic chemistry due selectivity of 15.8%. The STY and fraction of HA in total
to the proposal of a reaction coupling strategy or tandem alcohols are 70.6 mg gcat−1 h−1 and 89.9%, respectively. When
catalysis in COx hydrogenation.8 This strategy holds great CZA and K-CMZF are combined by powder mixing, the
potential in breaking the limitations of CO2 conversion and resulting CO2 conversion and product selectivity are quite
different, highly dependent on the CZA/K-CMZF mass ratio.
product selectivity. This is achieved mainly by promoting the
As the CZA/K-CMZF mass ratio decreases from 2:1 to 1:1
formation or transfer/migration of key reaction intermediates
and further to 1:2, the CO2 conversion increases first and then
via introducing other catalytic components in synergy that shift
drops, peaking at 42.3% at the mass ratio of 1:1. As for the
the equilibrium toward reaction.8a It is highly desirable to
achieve the efficient HAS from direct CO2 hydrogenation via
tandem catalysis. Back in 1999, Inui et al. first reported Received: April 8, 2021
multifunctional Fischer−Tropsch type composite catalysts (a Revised: June 27, 2021
Fe-based catalyst combined with a Cu-based catalyst) for Published: July 8, 2021
effective ethanol synthesis from CO2 hydrogenation.9 They
attributed the improved activity to the optimization of the
catalyst reduction property over composite catalysts, but the

© 2021 American Chemical Society https://doi.org/10.1021/acscatal.1c01610

8978 ACS Catal. 2021, 11, 8978−8984
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Table 1. Catalytic Performance of CO2 Hydrogenation over Various Catalystsa

products selectivity (%)
catalyst CO2 conversion (%) CO HCb C1OHc C2+OHd C2+OH/ROH (wt %) C2+OH STYe (mg gcat−1 h−1)
CZA 26.8 90.9 0.0 9.1 0.0 0.0 0.0
K-CMZF 30.4 31.1 52.0 1.2 15.8 89.9 70.6
K-CMZFf 20.1 50.4 36.1 1.3 10.7 86.4 71.2
CZA(2)/K-CMZF(1)g 29.0 34.2 50.5 3.3 11.9 72.2 50.6
CZA(1)/K-CMZF(1) 42.3 13.8 67.6 1.3 17.4 90.2 106.5 (213.0)
CZA(1)/K-CMZF(2) 34.3 23.7 58.2 1.7 16.4 87.2 81.8
a
Reaction conditions: 5 MPa, CO2/H2 = 1/3, 6 L gcat−1 h−1, and 320 °C. bHydrocarbons. cMethanol. dHigher alcohols. eThe space time yield
(STY) of C2+OH based on the mass of total catalyst. The STY of C2+OH based on the mass of K-CMZF shown in parentheses. f12 L gcat−1 h−1.
g
CZA(2)/K-CMZF(1) prepared by powder mixing of CZA and K-CMZF with mass ratio of 2:1.

Figure 1. Results of CO2 hydrogenation over the catalysts packed in different manners. (a) CO2 conversion and products selectivity, (b) alcohol
distribution and STY, and (c) HC distribution and α over a series of CZA/K-CMZF multifunctional catalysts (CZA/K-CMZF mass ratio of 1)
with different integration manners. Reaction conditions: 5 MPa, CO2/H2 = 1/3, 6 L gcat−1 h−1, and 320 °C.

product distribution, the HA and HC (hydrocarbons) reduction to CO or methanol) improved ethanol production
selectivity show the same trend as CO2 conversion while the activity over their Fe-based FT-type catalysts in CO 2
CO selectivity shows the opposite. Considering K-CMZF is hydrogenation. The strong catalytic synergy between different
the primary catalyst for the synthesis of C2+ products with CO functionalities needs to be clarified in depth.
as the key intermediate, we can reason out that the enhanced The proximity effect between CZA and K-CMZF in the
CO2 conversion is driven by the fast conversion of the CO direct CO2 hydrogen to HA was also investigated by
intermediate to HA and HC. The CZA component mainly comparing different catalyst filling configurations. In this series
catalyze rWGSR, which can provide abundant surface CO of catalysts, the CZA/K-CMZF mass ratio was fixed at 1:1. As
intermediates for C2+ product synthesis catalyzed by K-CMZF. shown in Figure 1a, Table S1 and Figure S2, for the catalysts
We thus believe that a proper ratio of the two components can with a dual bed manner (model a and b), the CO2 conversion
facilitate the rate match for the tandem catalysis in HAS. is only 24−26%. And the HA selectivity and STY are 12−14%
Surprisingly, the STY of HA reaches up to 106.5 mg gcat−1 h−1 and 45−47 mg gcat−1 h−1, respectively (Figure 1b). Note that
with an HA fraction of 90.2% in total alcohols when the mass the fraction of light olefins decreases from 15.0% to 1.7% when
ratio of CZA/K-CMZF is 1, much higher than other complex K-CMZF is loaded above CZA instead of CZA loaded above
catalysts. When comparing the catalytic performance at the K-CMZF (Figure 1c), indicating that the alkenes produced
same space velocity on a basis of K-CMZF (12 L gK‑CMZF−1 from K-CMZF tend to be hydrogenated to alkanes by CZA.
h−1), the multifunctional catalyst shows 1.7 times higher HA When shortening the distance of the two components by
selectivity (17.4% versus 10.7%) and 3 times higher HA STY granule mixing, the CO2 conversion increases to 32.1% with
(213.0 mg gK‑CMZF−1 h−1 versus 71.2 mg gK‑CMZF−1 h−1) than CO selectivity decreasing to 24.1%. And the HA STY increases
the sole K-CMZF. The significantly enhanced productivity and to 65.1 mg gcat−1 h−1. These results led us to question whether
striking comparison imply a strong synergistic effect between closer contact between two components can accelerate the
CZA and K-CMZF. Such enhanced activity is similar to the conversion of CO2 to CO and subsequent CO to HA. For the
reported composite catalysts by Inui et al.9 The introduction of catalyst with powder mixing, the highest CO2 conversion
a Cu-based catalyst component (a function of CO2 partial (42.3%), HA selectivity (17.4%), and STY (106.5 mg gcat−1
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Figure 2. CO2 conversion and product selectivity over CZA/K-CMZF multifunctional catalyst (CZA/K-CMZF mass ratio of 1, powder mixing) at
different (a) reaction temperatures, (b) reaction pressures, and (c) WHSV. (d) Correlation between CO2 conversion and CO selectivity under
different reaction conditions. Standard reaction conditions: 5 MPa, CO2/H2 = 1/3, 6 L gcat−1 h−1, and 320 °C.

h−1) with an HA fraction of 90.2% are obtained. The chain result, the multifunctional catalyst exhibits the highest CO2
growth probability of HC (0.65) is higher than that for other conversion and HA selectivity because of the accelerated
catalysts. This implies that this catalyst configuration is the consumption of CO at 5 MPa. Increasing pressure also affects
most conducive to HAS and C−C coupling reactions. We the reaction rate kinetically. The increase in the partial pressure
believe that a short distance between CZA and K-CMZF of H2 facilitates hydrogenation, which is reflected by the
would facilitate the migration of the CO intermediate, actually decrease in the fraction of light olefins. Also the increased
adsorbed *CO species rather than gaseous CO as the key coverage of adsorbed *CO species facilitates the formation of
linker in this tandem catalysis. However, further shortening the HA, hence leading to the increase of HA STY. We further
distance with mortar mixing leads to a reduction of catalytic investigated the impact of WHSV. As shown in Figure 2c,
activity. Note that the fraction of light olefins increases to Figure S6, and Table S4, when decreasing the WHSV, the CO2
11.3%, reflecting that the hydrogenation of light olefins conversion and HA selectivity both increase while the CO
catalyzed by CZA is inhibited. We find that the CZA selectivity decreases. The highest CO2 conversion (46.0%) and
component can be poisoned by K from K-CMZF when overly HA selectivity (19.5%) and the lowest CO selectivity of 9.6%
close proximity occurs, hence reducing its hydrogenation can be obtained at 3 L gcat−1 h−1. This is because the long
ability (Figure S3). We therefore conclude that appropriate contact time facilitates the conversion of *CO kinetically by
proximity between CZA and K-CMZF is critical to highly increasing the residence time of *CO on the catalyst surface.
active CO2 hydrogenation to HA. Additionally, long contact time also promotes the fraction of
We further investigated the effects of reaction conditions HA in total alcohols and C5+ HC in total hydrocarbons,
such as temperature, pressure, and weight hourly space velocity implying the improved chain growth ability. When comparing
(WHSV) on the catalytic performance over the optimized the catalytic performance of K-CMZF composition between
CZA/K-CMZF catalyst with the powder mixing configuration. sole K-CMZF and CZA/K-CMZF multifunctional catalysts,
As shown in Figure 2a, Figure S4, and Table S2, high the higher WHSV further enlarges the performance gap
temperature is in favor of the conversion of CO2 and the between these two catalysts due to the low conversion rate of
formation of HA and HC. The raised selectivity and STY of CO intermediate (Figure S7 and Table S5). The highest HA
HA at high temperature suggest that HAS is still under kinetic STY of 114.2 mg gcat−1 h−1 (2.42 mmol gcat−1 h−1) was
control. As shown in Figure 2b, Figure S5, and Table S3, high obtained at 9 L gcat−1 h−1, which has ranked in the top among
pressure facilitates the conversion of CO2 and the selectivity of the reported catalysts in the literature (Table S6). It is worth
HA and HC. Since the reactions of COx hydrogenation to HA noting that the selectivity toward valuable products (e.g.,
and HC are highly volume-sensitive according to the alcohols and C2+ hydrocarbons) can be tuned at 63.5−81.1%
stoichiometry, higher pressure would favor the formation of at a high level of CO2 conversion (34.9−46.0%). More than
HA and HC thermodynamically, according to Le Chatelier’s that, this catalyst also shows great stability in a 60 h time-on-
principle. Considering that the pressure has no effect on stream (TOS) test (Figure S8).
rWGSR thermodynamically, we can calculate the CO Figure 2d displays a comprehensive comparison of CO2
conversion, assuming that HA and HC both come from CO. conversion and CO selectivity over our multifunctional catalyst
With the pressure increasing from 2 to 5 MPa, the CO under different reaction conditions. It is found that higher CO2
conversion is remarkably improved from 33.7% to 86.0%. As a conversion generally locates at a region of lower CO selectivity,
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Figure 3. In situ DRIFTS characterization of CO2 hydrogenation taken under 0.3 MPa CO2/H2 flow of 30 mL min−1 at 250 °C. (a) DRIFTS
spectra over CZA/K-CMZF multifunctional catalyst. (b and c) Dynamic IR peak intensity of CH4 (3016 cm−1), *C2H5O (2928 cm−1), CO (2112
cm−1), and bri-CO (1919 cm−1) over (b) K-CMZF and (c) CZA/K-CMZF catalysts at 250 °C.

suggesting that the high CO2 conversion is strongly associated In situ diffuse reflectance infrared Fourier transform
with the sufficient consumption of CO. The highest CO2 spectroscopy (DRIFTS) tests were performed to study the
conversion is obtained at high temperature, high pressure, and reaction mechanism of CO 2 hydrogenation over the
low WHSV. Harsh conditions can kinetically promote the monocomponent and complex catalysts. For the sole CZA
conversion of adsorbed CO produced from rWGSR rather catalyst (Figure S15), gaseous CO (2250−2000 cm−1) is
than its direct desorption to gaseous CO. As a result, driven by produced during CO2 hydrogenation.12 This indicates that the
fast *CO consumption, the CO2 conversion goes up while the CZA component mainly catalyzes rWGSR. As for the K-
CO selectivity drops. This reveals the important role of the CMZF catalyst (Figure S16), *HCOO (2823/2766/2679/
*CO intermediate in CO2 hydrogentaion to HA. Moreover, 1603/1391/1352 cm−1) and *CH3O (1082 cm−1) are
the catalytic results by adding CO into the CO2/H2 feed gas observed, and they become weak as the reaction goes on.13
verified that the introduction of CO significantly accelerated Along with the growth of gaseous CO, the bands of *C2H5O
the formation rate of HA (Table S7 and Figure S9). (2963/2928/2856/1095 cm−1) appear and intensify.6a−c,13a
The structural transformation of the catalyst was evaluated Additionally, we can see a weak band at 3016 cm−1, which is
by transmission electron microscopy (TEM) and X-ray assigned to gaseous CH4,6b,c coming from K-CMZF catalyzed
CO dissociation and hydrogenation. In general, the K-CMZF
diffraction (XRD; Figures S10−S12). Numerous 5−10 nm
component is capable of catalyzing HAS via a CO insertion
Cu nanoparticles surrounded by ZnO are observed, primarily
mechanism as we have reported before.6b,c
belonging to the CZA component. We can also recognize the
The spectra of the CZA/K-CMZF multifunctional catalyst
Cu-MgCO3 interfaces and Fe5C2 phase ascribed to the K- are shown in Figure 3a and Figure S17. The peaks of
CMZF component. The elemental mapping images confirm adsorbates are similar to those of K-CMZF, indicating the
the high dispersion of various metals and the tight touch same reaction pathway of CO2 hydrogenation to HA via CO
between CZA and K-CMZF, which is critical to the strong insertion over K-CMZF and CZA/K-CMZF.6c The differences
synergistic effect in catalysis. As for the CZA/K-CMZF catalyst are peak intensities of gaseous CH4, CO, and *C2H5O species
after the TOS test, the diffraction peaks have almost no as well as a new peak at 1919 cm−1 ascribed to bridging CO
change, suggesting a good stability during CO2 hydrogenation. adsorption (bri-CO) on a multifunctional catalyst.6c,12b The
The chemical state of Fe species was further studied by dynamic peak intensity changes of gaseous CH4, gaseous CO,
Mössbauer and XPS spectra (Figures S13 and S14 and Table *C2H5O, and bri-CO species are further compared in Figure
S8). The bulk phase of spent catalysts was mainly in the type of 3b and c. The band of gaseous CO (2112 cm−1) on CZA/K-
FeO.10 A small amount of FeCx was probably formed on the CMZF rapidly strengthens and reaches a maximum at 10 min
surface of spent catalysts from combined XPS and XRD (Figure 3c), while that on K-CMZF gradually increases and
analyses.11 reaches a platform after 60 min (Figure 3b). This suggests that
8981 https://doi.org/10.1021/acscatal.1c01610
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the rWGSR is significantly accelerated with the addition of the Scheme 1. Proposed Reaction Pathway and Proximity Effect
CZA component. The bri-CO and gaseous CH4 on CZA/K- for CO2 Hydrogenation to HA over the CZA/K-CMZF
CMZF are both stronger than that on K-CMZF, which implies Multifunctional Catalyst
the enhanced transformation of CO2 to CH4 via CO
intermediate. Considering that CZA exhibits almost no activity
in the alkylation reaction, the raised generation of CH4 is more
likely to be produced from K-CMZF. We can postulate that
CO produced on CZA migrates to K-CMZF to accelerate the
production of CH4. In summary, the CZA and K-CMZF
components in the multifunctional catalyst show strong
synergy in catalyzing rWGSR and CO conversion.
CO chemisorption tests were then performed to gain more
information about the synergetic effect in the CZA/K-CMZF
multifunctional catalyst. CZA shows weak CO adsorption
strength, while K-CMZF shows relatively strong CO
adsorption capacity (Figure S18). As for CZA/K-CMZF, the
account of the low content of CO in feed gas or the low
weak and medium strong CO adsorption both decrease, while
coverage of chemisorbed CO (*CO) on the catalyst surface.
strong CO adsorption increases accompanied by the
As shown in Scheme 1, the CZA is proved to promote rWGSR,
generation of more CO2. This indicates that the multifunc-
and the produced CO species (*CO) is weakly adsorbed on its
tional catalyst possesses better CO adsorption and activation
surface and easily desorb to gaseous CO when CZA is too far
ability. CO desorption under a H2/Ar flow was further
away from K-CMZF. When K-CMZF is close to CZA, *CO
performed to study the activation and conversion of CO. The
can migrate to the surface of K-CMZF and participate in the
desorption temperature of CH4 on K-CMZF is lower than that
following CO conversion to HA. The proximity between the
on CZA (Figure S19), suggesting the stronger CO dissociative
two components determines the migration of chemisorbed
ability of K-CZMF.6c,14 The CZA/K-CMZF composite
*CO, which significantly affects the conversion of CO to HA.
possesses multiple sites for CO dissociation, but the desorption
This can explain the higher activity of the powder mixing
peak at 300−400 °C matches the K-CMZF well, which
catalyst than dual bed and granule stacking catalysts. However,
supports K-CMZF as the main component for CO dissociation
the much closer contact between CZA and K-CMZF (mortar
under reaction temperature. The sole K-CMZF catalyst shows
mixing) leads to the drop of CO2 conversion and HA
various CO nondissociative activation sites which are necessary
selectivity, probably due to the migration or ion exchange of an
for HAS on itself.1b,c,3 After the introduction of the CZA
active metallic ion (e.g., K+), which could weaken the
component, the CO adsorption amount is enhanced. Note that
hydrogenation ability.8b,d,e So, a proper proximity like powder
the weak CO desorption (153 °C) on CZA reduces and a new
mixing catalyst is most favorable for CO2 hydrogenation to HA
peak at 213 °C appears which is attributed to the CO in this work.
desorption on the K-CMZF component. This indicates the In summary, we have successfully constructed a multifunc-
easy migration of *CO between two components, and CZA tional catalyst by formulating CZA and K-CMZF components,
acts as the main window for *CO desorption. We can conclude which exhibits a superior catalytic activity in direct CO2
that the *CO species formed on CZA can migrate to K-CMZF hydrogenation to HA. Over the multifunctional catalyst,
for further reaction. Moreover, the desorption of strongly CZA is responsible for rWGSR, and K-CMZF could catalyze
adsorbed CO shifts to a higher temperature when compared to the COx-to-HA reaction via CO insertion. The strong synergy
sole K-CMZF, suggesting the enhancement of adsorption between CZA and K-CMZF ensures the rate matching of
strength of the catalyst to CO, just like what we have found rWGSR and HAS. A proper proximity is critical to accelerating
before. Additionally, the CO2 chemisorption tests further the transfer of the *CO intermediate from CZA to K-CMZF,
confirm the migration of produced *CO species between CZA thus improving the productivity of HA. This work provides a
and K-CMZF components (Figure S20). In summary, CO promising way for the rational design of multifunctional
activation and conversion are promoted by the synergistic catalysts to realize the highly active HAS from CO 2
effect between CZA and K-CMZF components, hence giving hydrogenation.

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the improved HAS activity.
It is found that the synergetic effect and proximity effect are ASSOCIATED CONTENT
two key points determining the catalytic performance in CO2 *
sı Supporting Information
hydrogenation to HA. Based on the analysis of DRIFTS and The Supporting Information is available free of charge at
TPSR results, we can conclude that the CZA component is in https://pubs.acs.org/doi/10.1021/acscatal.1c01610.
favor of CO formation and the K-CMZF component is in
charge of the conversion of COx to HA via the CO insertion Experimental section, discussion on the catalytic
mechanism (Scheme 1). The strong synergy between the two performance, discussion on the effect of reaction
components with a moderate mass ratio (e.g., 1:1) could conditions, and supplementary figures and tables
realize the continuous and rapid transformations of CO2 to (PDF)
*CO and *CO to HA because of the rate match of two
reactions. The effect of proximity on catalytic performance is
complicated. Note that CO is the key intermediate in CO2-to-
■ AUTHOR INFORMATION
Corresponding Authors
HA reaction and its conversion is of great importance to the Xinlin Hong − College of Chemistry and Molecular Sciences,
HAS activity.3a,4a,5b,6b However, the CO-to-HA reaction is Wuhan University, Wuhan 430072, China; Email: hongxl@
severely limited by kinetics rather than thermodynamics on whu.edu.cn
8982 https://doi.org/10.1021/acscatal.1c01610
ACS Catal. 2021, 11, 8978−8984
ACS Catalysis pubs.acs.org/acscatalysis Letter

Guoliang Liu − College of Chemistry and Molecular Sciences, 2019, 58, 11242−11247. (b) Zhang, S.; Liu, X.; Shao, Z.; Wang, H.;
Wuhan University, Wuhan 430072, China; orcid.org/ Sun, Y. Direct CO2 Hydrogenation to Ethanol over Supported Co2C
0000-0003-1575-254X; Email: liugl@whu.edu.cn Catalysts: Studies on Support Effects and Mechanism. J. Catal. 2020,
382, 86−96.
Authors (6) (a) Ding, L.; Shi, T.; Gu, J.; Cui, Y.; Zhang, Z.; Yang, C.; Chen,
Di Xu − College of Chemistry and Molecular Sciences, Wuhan T.; Lin, M.; Wang, P.; Xue, N.; Peng, L.; Guo, X.; Zhu, Y.; Chen, Z.;
University, Wuhan 430072, China Ding, W. CO2 Hydrogenation to Ethanol over Cu@Na-Beta. Chem.
Hengquan Yang − School of Chemistry and Chemical 2020, 6, 2673−2689. (b) Xu, D.; Ding, M.; Hong, X.; Liu, G.; Tsang,
S. C. E. Selective C 2+ Alcohol Synthesis from Direct CO 2
Engineering, Institute of Molecular Science, Shanxi University,
Hydrogenation over a Cs-Promoted Cu-Fe-Zn Catalyst. ACS Catal.
Taiyuan 030006, China; orcid.org/0000-0001-7955- 2020, 10, 5250−5260. (c) Xu, D.; Ding, M.; Hong, X.; Liu, G.
0512 Mechanistic Aspects of the Role of K Promotion on Cu-Fe-Based
Shik Chi Edman Tsang − Wolfson Catalysis Centre, Catalysts for Higher Alcohol Synthesis from CO2 Hydrogenation.
Department of Chemistry, University of Oxford, Oxford OX1 ACS Catal. 2020, 10, 14516−14526.
3QR, United Kingdom (7) Chen, Y.; Choi, S.; Thompson, L. T. Low Temperature CO2
Complete contact information is available at: Hydrogenation to Alcohols and Hydrocarbons over Mo2C Supported
Metal Catalysts. J. Catal. 2016, 343, 147−156.
https://pubs.acs.org/10.1021/acscatal.1c01610
(8) (a) Zhou, W.; Cheng, K.; Kang, J.; Zhou, C.; Subramanian, V.;
Zhang, Q.; Wang, Y. New Horizon in C1 Chemistry: Breaking the
Author Contributions Selectivity Limitation in Transformation of Syngas and Hydro-
All authors have given approval to the final version of the genation of CO2 into Hydrocarbon Chemicals and Fuels. Chem. Soc.
manuscript. Rev. 2019, 48, 3193−3228. (b) Gao, P.; Li, S.; Bu, X.; Dang, S.; Liu,
Funding Z.; Wang, H.; Zhong, L.; Qiu, M.; Yang, C.; Cai, J.; Wei, W.; Sun, Y.
The National Natural Science Foundation of China, the China Direct Conversion of CO2 to Liquid Fuels with High Selectivity over
National Key Research and Development Plan Project, the a Bifunctional Catalyst. Nat. Chem. 2017, 9, 1019−1024. (c) Li, Z.;
Fundamental Research Funds for Central Universities, and the Wang, J.; Qu, Y.; Liu, H.; Tang, C.; Miao, S.; Feng, Z.; An, H.; Li, C.
Major Scientific and Technological Project of Shanxi Province Highly Selective Conversion of Carbon Dioxide to Lower Olefins.
ACS Catal. 2017, 7, 8544−8548. (d) Wei, J.; Ge, Q.; Yao, R.; Wen,
of China. Z.; Fang, C.; Guo, L.; Xu, H.; Sun, J. Directly Converting CO2 into a
Notes Gasoline Fuel. Nat. Commun. 2017, 8, 15174. (e) Gao, P.; Dang, S.;
The authors declare no competing financial interest.

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Li, S.; Bu, X.; Liu, Z.; Qiu, M.; Yang, C.; Wang, H.; Zhong, L.; Han,
Y.; Liu, Q.; Wei, W.; Sun, Y. Direct Production of Lower Olefins from
ACKNOWLEDGMENTS CO2 Conversion via Bifunctional Catalysis. ACS Catal. 2018, 8, 571−
This work is financially supported by the National Natural 578. (f) Lin, T.; Qi, X.; Wang, X.; Xia, L.; Wang, C.; Yu, F.; Wang, H.;
Science Foundation of China (21872106), the China National Li, S.; Zhong, L.; Sun, Y. Direct Production of Higher Oxygenates via
Syngas Conversion over a Multifunctional Catalyst. Angew. Chem., Int.
Key Research and Development Plan Project Ed. 2019, 58, 4627−4631. (g) Luan, X.; Ren, Z.; Dai, X.; Zhang, X.;
(2018YFB1502000), the Fundamental Research Funds for Yong, J.; Yang, Y.; Zhao, H.; Cui, M.; Nie, F.; Huang, X. Selective
Central Universities (2042019kf0019, 2042019kf022), and the Conversion of Syngas into Higher Alcohols via a Reaction-Coupling
Major Scientific and Technological Project of Shanxi Province Strategy on Multifunctional Relay Catalysts. ACS Catal. 2020, 10,
of China (20201102005).

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2419−2430. (h) Zhou, W.; Kang, J.; Cheng, K.; He, S.; Shi, J.; Zhou,
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