Performance For CO2 Hydrogenation Research Articles

Promotion effects of oxygen vacancies on activity of Na-doped CeO2 catalysts for reverse water gas shift reaction

CeO2-based catalysts have been widely used in the CO2 hydrogenation process. The oxygen vacancies on CeO2 resulted from Na ion incorporation play a vital role in CO2 conversion activity, the effect of Na+ ion-doped in CeO2 during CO2 hydrogenation was rarely studied. In this work, the LN-CeO2 catalysts with different nNaOH:nCe ratios were prepared with liquid nitrogen(Liquid Nitrogen-CeO2, LN-CeO2), and the effect of the nNaOH:nCe ratio on the microstructure of the LN-CeO2 catalysts were evaluated. The best CO2 hydrogenation performance was achieved by LN-CeO2-100 with a CO production rate of 3.90 mol/gcat·h at 800 °C (100% CO selectivity). The kinetic results indicated that the CO2 hydrogenation performance difference among these LN-CeO2 catalysts resulted from the CO2 activation process. Oxygen vacancies could enhance CO2 activation on the surface of LN-CeO2, and oxygen vacancies displayed a linear correlation relationship with the Na content doped in LN-CeO2. The highest concentration of oxygen vacancies resulted from Na ion incorporated and lower CO2 reaction order was closely related to CO2 hydrogenation performance of LN-CeO2-100. These results will give insight into the Na effect on the CO2 hydrogenation mechanism over CeO2.

Boosting the Catalytic Performance of CuOx in CO2 Hydrogenation by Incorporating CeO2 Promoters

AbstractCopper is one of the most promising components in CO2 hydrogenation reactions, however, it still seriously suffers from the lower capability in CO2 activity, as well as poor durability. Herein, a novel copper‐cerium mixed metal oxide is fabricated via a controllable surface deposition route, showing excellent catalytic performance in CO2 hydrogenation. Of particular note, among the various samples with tunable Cu/Ce molar ratios, the obtained CuOx‐5CeO2 containing 0.42% Ce exhibits the highest catalytic activity with ≈31% CO2 conversion and 98% CO selectivity at 380 °C, as well as an excellent stability for 50 h. The as‐prepared catalysts are then characterized by H2‐temperature‐programmed reduction, CO2‐termperature programmed desorption, and in situ diffuse reflectance infrared Fourier transform spectroscopy to explore the possible reaction pathways. The results indicate the significance of the interactions between CuOx and CeO2, which can facilitate the activation of H2 and CO2 simultaneously, to promote the formation of formate intermediates.

Dynamic structural evolution of iron catalysts involving competitive oxidation and carburization during CO2 hydrogenation.

Identifying the dynamic structure of heterogeneous catalysts is crucial for the rational design of new ones. In this contribution, the structural evolution of Fe(0) catalysts during CO2 hydrogenation to hydrocarbons has been investigated by using several (quasi) in situ techniques. Upon initial reduction, Fe species are carburized to Fe3C and then to Fe5C2. The by-product of CO2 hydrogenation, H2O, oxidizes the iron carbide to Fe3O4. The formation of Fe3O4@(Fe5C2+Fe3O4) core-shell structure was observed at steady state, and the surface composition depends on the balance of oxidation and carburization, where water plays a key role in the oxidation. The performance of CO2 hydrogenation was also correlated with the dynamic surface structure. Theoretical calculations and controll experiments reveal the interdependence between the phase transition and reactive environment. We also suggest a practical way to tune the competitive reactions to maintain an Fe5C2-rich surface for a desired C2+ productivity.

Boosting CO2 hydrogenation performance for light olefin synthesis over GaZrOx combined with SAPO-34

A highly active and selective GaZrOx/SAPO-34 bifunctional catalyst was developed for CO2 hydrogenation into C2=–C4=. A high C2=–C4= selectivity of 88.8% at CO2 conversion of 26.7% was achieved, and the olefin yield reached 11.3%, outperforming the previous reports. As Ga:Zr atomic ratio increases, the surface oxygen vacancy content (OV), responsible for CO2 activation, firstly increases from 22.5% to 32.6% and then decreases to 15.4%, while the H2 dissociation ability produced by Ga site increases gradually. Activated CO2 at Zr–OV–Zr site could either react with Ga–Hδ– to form HCOO* , then successive hydrogenation to CH3O* intermediate, or combine with O–Hδ+ to form COOH* , followed by dissociation to form CO. The formation of CH3O* or CO is competitive, which highly depends on the H2 dissociation ability, only the moderate H2 dissociation ability benefits CO2 hydrogenation to CH3O* at high temperature, leading to a high C2=–C4= yield.

PdCu supported on dendritic mesoporous CexZr1-xO2 as superior catalysts to boost CO2 hydrogenation to methanol

A dendritic PdCu/Ce0.3Zr0.7O2 (PdCu/CZ-3) catalyst with uniform spherical morphology was prepared for boosting the catalytic performance of CO2 hydrogenation to methanol (MeOH). The open dendritic pore channels and small particle sizes could reduce not only the diffuse resistance of reactants and products but also increase the accessibility between the active sites (PdCu and oxygen vacancy) and the reactants (H2 and CO2). More spillover hydrogen could be generated due to the highly dispersed PdCu active metals over the PdCu/CZ-3 catalyst. PdCu/CZ-3 can stimulate the generation of more Ce3+ cations, which is beneficial to produce more oxygen vacancies on the surface of the CZ-3 composite. Spillover hydrogen and oxygen vacancy could promote the formate and methoxy routes over PdCu/CZ-3, the primary intermediates producing MeOH. PdCu/CZ-3 displayed the highest CO2 conversions (25.5 %), highest MeOH yield (6.4 %), highest PdCu-TOFMeOH (7.7 h−1) and superior 100 h long-term stability than those of other PdCu/CexZr1-xO2 analogs and the reference PdCu/CeO2 and PdCu/ZrO2 catalysts. Density functional theory (DFT) calculations and in situ DRIFTS were performed to investigate the CO2 − MeOH hydrogenation mechanism.

Effect of Precursors of Fe-Based Fischer–Tropsch Catalysts Supported on Expanded Graphite for CO2 Hydrogenation

Expanded graphite as a type of hydrophobic functional carbon material was innovatively selected as support for Fe-based Fischer–Tropsch catalysts. Through catalytic activity evaluation, ferric ammonium citrate was selected as the most suitable iron precursor for expanded graphite among ferric nitrate, ferric ammonium oxalate, ferric citrate, and ferric ammonium citrate. The catalyst with ferric ammonium citrate as the precursor and expanded graphite as support achieved the best CO2 hydrogenation performance with a CO2 conversion rate of 42.4%, a C2═–C4═ yield of 14.8%, and a CO selectivity of 8.3%. Furthermore, it was observed that the precursor that had better wettability and formed hydrogen bonds with support tended to generate smaller iron nanoparticles. In addition, nitrogen doping during catalyst calcination would cause differences in electronic properties and then influence the reducibility and carbonization of iron species.

Preparation of supported In2O3/Pd nanocatalysts using natural pollen as bio-templates for CO2 hydrogenation to methanol: Effect of acid-etching on template

The conversion of CO2 into value-added chemicals is an effective way to mitigate the environmental problems caused by huge anthropogenic CO2 emissions. Although In2O3/Pd catalyst possesses excellent catalytic performance in CO2 hydrogenation to methanol, the formation of Pd-In alloy on the catalyst surface greatly reduces the yield of methanol. Herein, we adopt a natural biomaterial (viz., rape pollen) as a template to synthesize hierarchically structured bio-In2O3 and bio-In2O3/Pd catalysts. In particular, we found that the pretreatment of pollen using hydrochloric acid (HCl) played a critical role in determining catalytic performance. A series of bio-In2O3 were prepared by using the pollen templates with different etching degrees, and then the bio-In2O3-x/Pd catalysts (x denoted as the amount of HCl, mL) were prepared using an impregnation-reduction method. It was surprising that the CO2 conversion of bio-In2O3–15/Pd catalyst was 8.2% with methanol selectivity of 74.7%, which was much better than the bio-In2O3–0/Pd (2.6% and 54.6%, respectively). The dramatic enhancement was due to that the acid-etched pollen template owns a hollow cage-like structure and abundant surface functional groups (-NH2 and -COOH), which is beneficial to the growth of In2O3 with a high amount of surface oxygen vacancies. Also, the bio-In2O3/Pd catalyst (prepared with untreated pollen template) was more prone to form Pd-In alloys as a result of the strong interaction between Pd with In2O3. In contrast, the In2O3 spatial distribution of bio-In2O3–15/Pd was more uniform with an appropriate interaction of Pd with In2O3 that inhibited the formation of Pd-In alloys. Even Pd loaded on commercial In2O3 exhibited inferior performance (3.4% CO2 conversion and 81% methanol selectivity) to bio-In2O3–15/Pd catalyst. Accordingly, the present work offers a green and efficient method to prepare supported In2O3/Pd catalysts by using the acid-etched pollen as a template.

Enhanced low-temperature catalytic performance in CO2 hydrogenation over Mn-promoted NiMgAl catalysts derived from quaternary hydrotalcite-like compounds

Mn-promoted NiMgAl mixed-oxide (NiMnx-LDO, x = 0, 5, 10, 15) catalysts derived from hydrotalcite were synthesized using co-precipitation for CO2 hydrogenation to synthetic natural gas. By regulating Mn contents, NiMn5-LDO delivered the most excellent catalytic performance, being about 2 times higher than that of undoped NiMn0-LDO catalyst (TOF of NiMn5-LDO and NiMn0-LDO: 0.61 s−1 vs 0.31 s−1 @ 240 °C). Through extensive characterization, it was found that Mn dopants promoted the reduction of bulk NiO through tuning the interaction between Ni and Mg(Mn)AlOx support. A high surface ratio of Ni0/Ni2+ was achieved over NiMn5-LDO. Furthermore, the surface basicity strength was tailored by Mn dopants. With 5 wt% of Mn, NiMn5-LDO catalyst showed a stronger medium-strength basicity and higher capacity of CO2 adsorption than others. Particularly, TOF indicates a good correlation with medium-strength basicity over NiMnx-LDO catalysts. The strong metal-support interaction originated from the hydrotalcite structure kept nickel uniformly dispersed, endowing to the improved catalytic performance.

Reduction treatment of nickel phyllosilicate supported Pt nanocatalysts determining product selectivity in CO2 hydrogenation

Catalyst design is one of the most critical factors in selectively converting CO2 and renewable H2 to value-added chemicals. In this work, Pt nanoparticles with an average size of 2.9 nm were uniformly loaded on hollow mesoporous nickel phyllosilicate which then underwent various reduction treatments to partial extraction of Ni atoms and formation of Ni-Pt bimetallic catalysts for the selective CO2 hydrogenation in a fixed bed reactor. Experimental results reveal that Pt nanoparticles supported on SiO2 are highly selective to CO via reversed water gas shift (RWGS) reaction with 100% CO selectivity, while Pt nanoparticles supported on nickel phyllosilicate show high selectivity for CH4, particularly, under high reduction temperature. By simply changing the reduction temperature or reaction pressure, the production selectivity can be facilely tuned, and the maximum CH4 selectivity achieved in the bimetallic Pt/Ni@phyllosilicate catalyst is 100%. The metallic Ni0 reduced from nickel phyllosilicate owns a high concentration of Lewis basic sites, which could enhance the adsorption strength of CO2 but prevent the dissociated adsorption. The diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) in different transient states were applied to study the mechanistic insights into how Ni-Pt dual sites tune the product selectivity. The results suggest that CO* over Pt site is the key species for CO2 conversion to CO, whereas the produced CO* could be further hydrogenated to CHxO* intermediate over Ni site, leading to the formation of CH4. The present work offers a new method to prepare Ni-Pt bimetallic catalysts with excellent CO2 hydrogenation performance towards CH4.

Promotion effect of iron addition on the structure and CO2 hydrogenation performance of Attapulgite/Ce0.75Zr0.25O2 nanocomposite supported Cu-ZnO based catalyst

• Fe introduction improves the surface dispersion of metallic Cu on CZF x K/ATP-CZO catalysts. • Medium Fe addition enhances the formation of surface adsorbed and lattcie oxygen species and ZnO-CZO interfaces. • In-situ DRIFT is adopted to explore the CO 2 adsorption mode and reaction intermediate species. • Methanol is synthesized over CZF 0.5 K/ATP-CZO catalyst with the highest CO 2 conversion and space time yield. A series of CZF x K/ATP-CZO catalysts (x= 0, 0.3, 0.5, 1.0, 1.5 and 2.0) are applied to clarify the effects of the iron addition on the catalytic performance of CO 2 hydrogenation to CH 3 OH. The physicochemical properties and catalytic mechanism were investigated by N 2 adsorption/desorption, XRD, TEM, N 2 O chemisorption, XPS, H 2 -TPR, CO 2 -TPD and in-situ DRIFT techniques. The best catalytic performance is achieved over CZF 0.5 K/ATP-CZO catalyst, exhibiting X CO2 = 17.5%, STY CH3OH = 0.108 g/g cat. ∙h and STY CO = 0.146 g/g cat. ∙h (T = 320°C, P = 6 MPa). The formation of dispersed surface metallic Cu species and larger number of surface adsorbed and lattcie oxygen species and ZnO-CZO interfaces are detected over CZF 0.5 K/ATP-CZO due to stronger interaction between dispersed metallic Cu particles on ZnO-Fe nano-cluster and ATP-CZO composite, resulting in the superior activation ability for H 2 and CO 2 respectively. Additionally, the evidence is provided by in-situ DRIFTS under the activity test temperature (320°C) that HCOO∗ and CO* species are preferable for accumulating over CZK/ATP-CZO catalyst without Fe addition while medium Fe-modified CZF x K/ATP-CZO catalysts (CZF 0.3 K/ATP-CZO, CZF 0.5 K/ATP-CZO) catalysts are benefitial to promote the transformation of HCOO∗ species to CH 3 OH. These excessive Fe-modified CZF x K/ATP-CZO catalysts (CZF 1.0 K/ATP-CZO, CZF 2.0 K/ATP-CZO) are more easily to produce CH 4 via formate pathway (CO 2 * → HCOO* → HCO* → CH* → CH 4 *). The abundant population and high transformation activity of formate intermediate species over CZF 0.5 K/ATP-CZO give a strong positive effect on the CO 2 hydrogenation to methanol performance. The strong interactions between dispersed metallic Cu species and larger number of surface adsorbed and lattcie oxygen species and ZnO-CZO interfaces give rise to favorable methanol synthesis performances over CZF0.5K/ATP-CZO catalyst.

Synergistic Effect of Alkali Na and K Promoter on Fe-Co-Cu-Al Catalysts for CO2 Hydrogenation to Light Hydrocarbons

Alkali metal K- and/or Na-promoted FeCoCuAl catalysts were synthesized by precipitation and impregnation, and their physicochemical and catalytic performance for CO2 hydrogenation to light hydrocarbons was also investigated in the present work. The results indicate that Na and/or K introduction leads to the formation of active phase metallic Fe and Fe-Co crystals in the order Na < K < K-Na. The simultaneous introduction of Na and K causes a synergistic effect on increasing the basicity and electron-rich property, promoting the formation of active sites Fe@Cu and Fe-Co@Cu with Cu0 as a crystal core. These effects are advantageous to H2 dissociative adsorption and CO2 activation, giving a high CO2 conversion with hydrogenation. Moreover, electron-rich Fe@Cu (110) and Fe-Co@Cu (200) provide active centers for further H2 dissociative adsorption and O-C-Fe intermediate formation after adsorption of CO produced by RWGS. It is beneficial for carbon chain growth in C2+ hydrocarbons, including olefins and alkanes. FeCoCuAl simultaneously modified by K-Na exhibits the highest CO2 conversion and C2+ selectivity of 52.87 mol% and 89.70 mol%, respectively.

In situ XPS studies of MoS2-based CO2 hydrogenation catalysts

Various formulations of Co, Ni and K modified MoS2-based catalysts were synthesized hydrothermally and compared in their catalytic performance in CO2 hydrogenation at 21 bar and 220 °C–330 °C. The products were CO, CH4 and methanol. The addition of K reduced the selectivity to CH4 and moved the maximum of the methanol formation rate to a higher temperature. The materials were characterized by N2 physisorption, temperature programmed oxidation, temperature programmed reduction, and x-ray diffraction spectra (XRD). Under reducing conditions the catalysts were stable until 700 °C and under oxidizing conditions until 300 °C. XRD had shown mainly a MoS2 phase, as well as metal sulfide in the cobalt and nickel promoted catalysts. Different species of Mo and O were observed under reaction conditions by in situ x-ray photoelectron spectroscopy (XPS). When switching from H2 to CO2 + H2 an increase in the amount of oxygen, both lattice oxygen and surface adsorbates, was observed as a consequence of CO2 addition and H2O formation in the reaction. The amount of lattice oxygen correlates with the minor amount of Mo(VI) detected. Increasing reaction temperature and thus conversion led to an increase of the O 1s signals at 533 eV assigned to surface OH, formate and adsorbed H2O. XPS measurements in CO2 + H2 feed showed an effect of K addition on the adsorbate-related O 1s peak, which appeared at lower binding energy (532 eV) and was assigned to carbonates. This may indicate a different reaction mechanism in the presence of the promoter.

Yttria-doped Cu/ZnO catalyst with excellent performance for CO2 hydrogenation to methanol

Revealing the origin of the enhanced performance on yttria (Y2O3) promoted Cu/ZnO based catalyst for methanol synthesis via CO2 hydrogenation is still challenging. To shed light upon the promotion effect of Y2O3 modifier on binary Cu/ZnO catalyst for CO2 hydrogenation reaction, a ternary Cu/ZnO/Y2O3 catalyst was synthesized via a citric acid coordination-assisted strategy. The developed Cu/ZnO/Y2O3 catalyst exhibited a remarkably higher Weight-time yeild of methanol (236.8 gMeOH gcat−1∙h − 1) and methanol selectivity (81.1%) in comparison to Cu/ZnO catalyst (159.6 gMeOH gcat−1∙h − 1 and 73.9%, respectively). Various characterizations results have uncovered the enhanced catalytic activity of Cu/ZnO/Y2O3 catalyst for methanol synthesis was associated with small size and highly dispersed Cu species and abundant surface adsorption sites as well as more Cu-ZnO interfaces with strong interaction. Moreover, the Cu/ZnO/Y2O3 catalyst displayed a superior weight-time yield of methanol with a time-on-stream of 100 h in comparison with classic Cu/ZnO catalyst. We anticipate that this basic design strategy will provide a novel alternative to expand opportunities to explore scalable, cost-effective catalysts for industrial methanol synthesis.

A Multi‐Parametric Catalyst Screening for CO2 Hydrogenation to Ethanol

AbstractThe direct hydrogenation of CO2 to higher alcohols has the potential to turn the main contributor of global warming into a valuable feedstock. However, for this technology to become attractive, more efficient and, especially, selective catalysts are required. Here we present a high throughput study on the influence of different promoters on the CO2 hydrogenation performance of Rh−SiO2 catalysts. Fe and K promoters were found to improve ethanol selectivity at the expense of undesired CH4. The best‐performing catalyst, with a composition 2 wt.% K, 20 wt.% Fe, and 5 wt.% Rh, displays an EtOH selectivity of 16 % at CO2 conversion level of 18.4 % and CH4 selectivity of 46 %. The combination of different characterization techniques and catalyst screening allowed us to unravel the role of each catalyst component in this complex reaction mechanism.

Solvothermal preparation of CuO-ZnO-ZrO2 catalysts for methanol synthesis via CO2 hydrogenation

Solvothermal preparation of CuO-ZnO-ZrO2 (CZZ) was realized using ethylene glycol as a solvent. The effects of solvothermal temperature (140–200 °C) on the properties of catalysts and catalytic performance in CO2 hydrogenation were studied. ICP-OES, N2 sorption, XRD, SEM-EDX, reactive N2O adsorption, XPS, H2-TPR, H2-TPD, and CO2-TPD were used as characterization tools. The data indicate that the CZZ-180 catalyst prepared at a solvothermal temperature of 180 °C has the smallest Cu crystallites and the largest surface area of Cu0, thus exhibiting the highest methanol yield. The effects of reaction temperature, pressure, and space velocity were also investigated.

CO2 hydrogenation to C5+ hydrocarbons over K‐promoted Fe/CNT catalyst: Effect of potassium on structure–activity relationship

Developing efficient catalysts for direct CO2 hydrogenation to fuel hydrocarbons is of great significance for the effective utilization of CO2, and C5+ selectivity is one critical indicator for the process economics. In this work, a series of K‐promoted Fe/CNT catalysts were prepared by the co‐impregnation method, and their catalytic performance for CO2 hydrogenation was studied in a slurry‐bed reactor. As a result, CO2 conversion and C5+ selectivity showed positive correlation with the increase of K/Fe ratio from 0 to 0.3, but further increase of K/Fe ratio above 0.3 slightly affected its. The catalyst with a K/Fe molar ratio of 0.3 achieved the best performance with CO2 conversion of 23.7% and C5+ selectivity of 56%. In addition, the structure–activity relationship of the catalyst was discussed based on various characterization results. K‐modified catalysts presented a higher specific surface area and stronger CO2 chemisorption, which helped to improve CO2 conversion and C5+ selectivity. However, excessive potassium loading caused a loss of specific surface area, reduction degree, and graphitization degree of the catalyst, which inhibited the CO2 chemisorption and the formation of C5+ hydrocarbons.

Catalytic consequences of the decoration of sodium and zinc atoms during CO2 hydrogenation to olefins over iron-based catalyst

This study unravels the effects of Na decoration and/or ZnO addition on the structures of Fe based catalysts, and the reaction pathways and the rate dependencies on both the composition of reactants and reaction temperature for CO2 hydrogenation to olefins, using kinetics and structure characterization by Raman spectroscopy, X-ray diffraction, and temperature-programmed CO reduction techniques. CO2 hydrogenation over Fe based catalysts occurs as a combination of the primary reverse water-gas-shift reaction to form CO and the subsequent CO hydrogenations to produce olefins and paraffins. Adding ZnO into Fe catalysts enhanced the rates of CO2 hydrogenation to all carbon containing products because ZnO facilitated the generation of iron carbide, as an active phase in Fe based catalysts, however, the relative rates among primary RWGS reactions, secondary CO hydrogenation to olefins and to paraffins were insensitive to the addition of Zn. Decoration of Na into Fe catalysts altered significantly the rate dependencies on both reactants and reaction temperature for olefins formation, which might be the results of the modification of the reducibility and surface identities of Fe catalysts by Na atoms, thus changed the rate ratios of paraffins and olefins. As results of decoration of Na and addition of Zn, the modified Fe based catalyst exhibits optimal performance for CO2 hydrogenation to olefins, which shows a CO2 conversion of 43 % with a selectivity of 54.1 % to high olefins, and a high olefins-to-paraffins ratio of 7.3.

Near ambient-pressure X-ray photoelectron spectroscopy study of CO2 activation and hydrogenation on indium/copper surface

Indium-based catalysts exhibit excellent performance for CO2 hydrogenation to methanol, yet their nature and chemical evolution under reaction conditions are still elusive, thus hindering an understanding of their reaction mechanism. In this work, near ambient-pressure X-ray photoelectron spectroscopy (NAP-XPS) is employed to investigate the chemical properties and the catalytic role of indium/copper model catalysts under CO2 hydrogenation conditions. We found that the deposition of In on the surface of a Cu foil led to the formation of Cu-In alloy, whereas upon CO2 exposure, In was partially oxidized to In2O3-x and Cu remains metallic. Due to the presence of In2O3-x, CO2 was activated on the surface of In/Cu samples mainly in the form of carbonate. In addition, compared with the pure In foil reference, both the fraction of oxygen vacancies and the coverage density of carbonate were higher on the In/Cu samples, indicating the promotion effect of Cu-In alloy in the activation of CO2. These results reveal the evolution of the active sites of indium/copper catalysts and inspire the design of advanced In-based bimetallic catalysts for CO2 hydrogenation.

Fe-Co-K/ZrO2 Catalytic Performance of CO2 Hydrogenation to Light Olefins

Fe-Co-K/ZrO₂ Catalytic Performance of CO₂ Hydrogenation to Light Olefins

Effect of alkali (Cs) doping on the surface chemistry and CO2 hydrogenation performance of CuO/CeO2 catalysts

The reaction of captured carbon dioxide with renewable hydrogen towards the eventual indirect production of liquid hydrocarbons via CO2 reduction to CO (reverse water-gas shift reaction, rWGS) is a promising pathway in the general scheme of worldwide CO2 valorization. Copper-ceria oxides have been largely employed as rWGS catalysts owing to their unique properties linked to copper-ceria interactions. Here, we report on the fine-tuning of CuO/CeO2 composites by means of alkali promotion. In particular, this work aims at exploring the effect of cesium doping (0–4 atoms Cs per nm2) on co-precipitated CuO/CeO2 catalysts under CO2 hydrogenation conditions. The as-prepared samples were characterized by N2 physisorption, X-ray diffraction (XRD), H2-temperature programmed reduction (H2-TPR), X-ray photoelectron spectroscopy (XPS), CO2-temperature programmed desorption (CO2-TPD), Fourier-transform infrared spectroscopy (FTIR) of pyridine adsorption and CO-diffuse reflectance Fourier-transform infrared spectroscopy (CO-DRIFTS). The results demonstrated that a low amount of Cs exerted a beneficial effect on CO selectivity, inhibiting, however, CO2 conversion. Specifically, a doping of 2 atoms Cs per nm2 offers > 96 % CO selectivity and equilibrium CO2 conversion at temperatures as low as 430 °C, whereas further increase in cesium loading had no additional impact. The present findings can be mainly interpreted on a basis of the alkali effect on the textural and acid/base properties; Cs doping results in a significant reduction of the surface area and thus to a lower population of active sites for CO2 conversion, whereas it enhances the formation of basic sites and the stabilization of partially reduced Cu+ species, favoring CO selectivity.