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The active site of the industrial Cu/ZnO/Al2O3 catalyst used in CO2 hydrogenation to methanol has been debated for decades. Grand challenges remain in the characterization of structure, composition, and chemical state, both microscopically and spectroscopically, and complete theoretical calculations are limited when it comes to describing the intrinsic activity of the catalyst over the diverse range of structures that emerge under realistic conditions. Here a series of inverse model catalysts of ZnO on copper hydroxide were prepared where the size of ZnO was precisely tuned from atomically dispersed species to nanoparticles using atomic layer deposition. ZnO decoration boosted methanol formation to a rate of 877 gMeOH kgcat−1 h−1 with ≈80 % selectivity at 493 K. High pressure in situ X‐ray absorption spectroscopy demonstrated that the atomically dispersed ZnO species are prone to aggregate at oxygen‐deficient ZnO ensembles instead of forming CuZn metal alloys. By modeling various potential active structures, density functional theory calculations and microkinetic simulations revealed that ZnO/Cu interfaces with oxygen vacancies, rather than stoichiometric interfaces, Cu and CuZn alloys were essential to catalytic activation. [ABSTRACT FROM AUTHOR]

The active site of the industrial Cu/ZnO/Al2O3 catalyst used in CO2 hydrogenation to methanol has been debated for decades. Grand challenges remain in the characterization of structure, composition, and chemical state, both microscopically and spectroscopically, and complete theoretical calculations are limited when it comes to describing the intrinsic activity of the catalyst over the diverse range of structures that emerge under realistic conditions. Here a series of inverse model catalysts of ZnO on copper hydroxide were prepared where the size of ZnO was precisely tuned from atomically dispersed species to nanoparticles using atomic layer deposition. ZnO decoration boosted methanol formation to a rate of 877 gMeOH kgcat−1 h−1 with ≈80 % selectivity at 493 K. High pressure in situ X‐ray absorption spectroscopy demonstrated that the atomically dispersed ZnO species are prone to aggregate at oxygen‐deficient ZnO ensembles instead of forming CuZn metal alloys. By modeling various potential active structures, density functional theory calculations and microkinetic simulations revealed that ZnO/Cu interfaces with oxygen vacancies, rather than stoichiometric interfaces, Cu and CuZn alloys were essential to catalytic activation. [ABSTRACT FROM AUTHOR]

It is of pivotal importance to develop efficient catalysts and investigate the intrinsic mechanism for CO2 methanation. Now, it is reported that PdFe intermetallic nanocrystals afforded high activity and stability for CO2 methanation. The mass activity of fct‐PdFe nanocrystals reached 5.3 mmol g−1 h−1, under 1 bar (CO2:H2=1:4) at 180 °C, being 6.6, 1.6, 3.3, and 5.3 times as high as that of fcc‐PdFe nanocrystals, Ru/C, Ni/C, and Pd/C, respectively. After 20 rounds of successive reaction, 98 % of the original activity was retained for PdFe intermetallic nanocrystals. Further mechanistic studies revealed that PdFe intermetallic nanocrystals enabled the maintenance of metallic Fe species via a reversible oxidation–reduction process in CO2 methanation. The metallic Fe in PdFe intermetallic nanocrystals induced the direct conversion of CO2 into CO* as the intermediate, contributing to the enhanced activity. [ABSTRACT FROM AUTHOR]

The active site of the industrial Cu/ZnO/Al2O3 catalyst used in CO2 hydrogenation to methanol has been debated for decades. Grand challenges remain in the characterization of structure, composition, and chemical state, both microscopically and spectroscopically, and complete theoretical calculations are limited when it comes to describing the intrinsic activity of the catalyst over the diverse range of structures that emerge under realistic conditions. Here a series of inverse model catalysts of ZnO on copper hydroxide were prepared where the size of ZnO was precisely tuned from atomically dispersed species to nanoparticles using atomic layer deposition. ZnO decoration boosted methanol formation to a rate of 877 gMeOH kgcat−1 h−1 with ≈80 % selectivity at 493 K. High pressure in situ X‐ray absorption spectroscopy demonstrated that the atomically dispersed ZnO species are prone to aggregate at oxygen‐deficient ZnO ensembles instead of forming CuZn metal alloys. By modeling various potential active structures, density functional theory calculations and microkinetic simulations revealed that ZnO/Cu interfaces with oxygen vacancies, rather than stoichiometric interfaces, Cu and CuZn alloys were essential to catalytic activation. [ABSTRACT FROM AUTHOR]

The active site of the industrial Cu/ZnO/Al2O3 catalyst used in CO2 hydrogenation to methanol has been debated for decades. Grand challenges remain in the characterization of structure, composition, and chemical state, both microscopically and spectroscopically, and complete theoretical calculations are limited when it comes to describing the intrinsic activity of the catalyst over the diverse range of structures that emerge under realistic conditions. Here a series of inverse model catalysts of ZnO on copper hydroxide were prepared where the size of ZnO was precisely tuned from atomically dispersed species to nanoparticles using atomic layer deposition. ZnO decoration boosted methanol formation to a rate of 877 gMeOH kgcat−1 h−1 with ≈80 % selectivity at 493 K. High pressure in situ X‐ray absorption spectroscopy demonstrated that the atomically dispersed ZnO species are prone to aggregate at oxygen‐deficient ZnO ensembles instead of forming CuZn metal alloys. By modeling various potential active structures, density functional theory calculations and microkinetic simulations revealed that ZnO/Cu interfaces with oxygen vacancies, rather than stoichiometric interfaces, Cu and CuZn alloys were essential to catalytic activation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Regardless of morphology, 3-fold S vacancy on MoS 2 is poisoned by O, retarding CO 2 + H 2. • Bridge S vacancy on MoS 2 destabilizes O, increasing the rate by 7 orders of magnitude. • Distinct mechanism is found on 3-fold (direct) and bridge S vacancy (associative) • Optimal S vacancy type is identified on MoS 2 , providing an alternative to noble metal. • Coordination of vacancy tuned activity illustrates a promising way to design catalyst. Vacancies, typically exist in various types and morphologies on the surfaces of transition metal compound catalysts, have been shown to play an important role in many catalytic reactions. However, identifying the optimal type and morphology of vacancy and the key factors that control its performance remains a significant challenge. By density functional theory calculations and microkinetic modeling, we show that compared to various threefold S vacancy morphologies on the basal plane, the lower coordination number at the bridge S vacancy of Mo edge on MoS 2 tunes the relative adsorption strength of key intermediates (such as O relative to OH). This not only increases CO 2 hydrogenation rate by 7–11 orders of magnitude, but also leads to clearly distinct mechanism (associative & redox). The large destabilization of O and low H coverage on the Mo edge also hinder C-O scission and hydrogenation (give CH 4 and CH 3 OH) relative to CO desorption, leading to almost 100% CO selectivity. The inexpensive MoS 2 catalyst provides an alternative to the traditional noble metal catalysts for reverse water gas shift, and the coordination number of vacancy modulated catalytic performance illustrates a promising way to design transition metal compound catalysts for other important reactions of technological interest. [ABSTRACT FROM AUTHOR]