Mechanistic insight into the catalytically active phase of CO2 hydrogenation on Cu/ZnO catalyst

Wu, Xiaohao; Xia, Guang-Jie; Huang, Zhen; Kumar, Deepak; Zhao, Hong; Zhang, Jie; Yun, Jimmy; Wang, Yang‐Gang

doi:10.1016/j.apsusc.2020.146481

Cited by 20 publications

(12 citation statements)

References 63 publications

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“…The hydrogenation of methoxy (*CH 3 O) to *CH 3 OH ( E a = 1.84 eV, Figures A and S2, Table S1) corresponds to the highest barrier among all the elementary steps involved. These results were consistent with the previous mechanistic studies on Cu-based catalysts, ,,− showing that the difficulties in converting *CO and *CH 3 O hindered the CH 3 OH production via the CO-hydrogenation. On Cu/Cs/ZnO(0001̅), the presence of Cs stabilized both reaction intermediates and TSs along the CO-hydrogenation pathway (Figure A).…”

Section: Resultssupporting

confidence: 92%

Cesium-Induced Active Sites for C–C Coupling and Ethanol Synthesis from CO₂ Hydrogenation on Cu/ZnO(0001̅) Surfaces

et al. 2021

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The efficient conversion of carbon dioxide, a major air pollutant, into ethanol or higher alcohols is a big challenge in heterogeneous catalysis, generating great interest in both basic scientific research and commercial applications. Here, we report the facilitated methanol synthesis and the enabled ethanol synthesis from carbon dioxide hydrogenation on a catalyst generated by codepositing Cs and Cu on a ZnO(0001̅ ) substrate. A combination of catalytic testing, X-ray photoelectron spectroscopy (XPS) measurements, and calculations based on density functional theory (DFT) and kinetic Monte Carlo (KMC) simulation was used. The results of XPS showed a clear change in the reaction mechanism when going from Cs/Cu(111) to a Cs/Cu/ ZnO(0001̅ ) catalyst. The Cs-promoting effect on C−C coupling is a result of a synergy among Cs, Cu, and ZnO components that leads to the presence of CH x and CH y O species on the surface. According to the DFT-based KMC simulations, the deposition of Cs introduces multifunctional sites with a unique structure at the Cu−Cs−ZnO interface, particularly being able to promote the interaction with CO 2 and thus the methanol synthesis predominantly via the formate pathway. More importantly, it tunes the CHO binding strongly enough to facilitate the HCOOH decomposition to CHO via the formate pathway, but weakly enough to allow further hydrogenation to methanol. The fine-tuning of CHO binding also enables a close alignment of a CHO pair to facilitate the C−C coupling and eventually ethanol synthesis. Our study opens new possibilities to allow the highly active and selective conversion of carbon dioxide to higher alcohols on widely used and low-cost Cu-based catalysts.

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Section: Resultssupporting

confidence: 92%

Cesium-Induced Active Sites for C–C Coupling and Ethanol Synthesis from CO₂ Hydrogenation on Cu/ZnO(0001̅) Surfaces

et al. 2021

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“…H 2 dissociation on metal surfaces was extensively investigated before . In Fischer–Tropsch synthesis (FTS) and methanol synthesis reactions catalyzed by Fe, , Co, − Ru, , and Cu − metals, H 2 readily dissociates homolytically on the metal surfaces to form chemically similar hydrogen atoms, which would recombine to form H 2 molecules and desorb from the surface at higher temperatures. In contrast, on oxide surfaces, H 2 could dissociate heterolytically to form hydride (H – ) and proton (H + ) species coordinating to the metal cation and oxygen anion, respectively.…”

Section: Introductionmentioning

confidence: 99%

H₂ Activation on Pristine and Substitutional ZnO(101̅0) and Cr₂O₃(001) Surfaces by Density Functional Theory Calculations

Luo

Liu

2022

J. Phys. Chem. C

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As a major component of syngas (a mixture of hydrogen and carbon monoxide), activation of hydrogen molecules on metal oxides plays a vital role in various hydrogenation reactions and synthesis of valuable chemicals. Herein, we present a density functional theory investigation of H 2 activation and subsequent dehydration over pristine and substituted ZnO(101̅ 0) and Cr 2 O 3 (001) surfaces. An ab initio thermodynamics study shows that Cr 1 substitution on ZnO(101̅ 0) and Zn 1 substitution on Cr 2 O 3 (001) are stable in a wide range of temperatures and pressures. The binding strength of H to the low-valent Zn cations is the weakest one, followed by the high-valent Cr cation and the lattice oxygen coordinated to Cr as wells as to Zn. Heterolytic dissociation is found to be preferential than the homolytic one. The pristine ZnO(101̅ 0) is active for H 2 dissociation, and the presence of Cr 1 increases the formation energy of oxygen vacancies and lowers the reactivity to H 2 dissociation. Although Cr 2 O 3 (001) is less active for H 2 dissociation, the presence of Zn 1 lowers the formation energy of oxygen vacancies and promotes the surface reactivity even higher than that of pristine ZnO(101̅ 0). The dissociated H species turn to recombine and form H 2 rather than reacting with the lattice oxygen to form H 2 O. The present work provides a deeper insight into H 2 activation over pristine and heterometal-atom-modified oxide surfaces and a rationale for the design of active catalysts for syngas conversion.

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“…As the temperature was increased, the OH bands gradually weakened, indicating that surface OHs were involved in the catalytic process. According to the theoretical study of CO 2 hydrogenation, 69,70 there are three main reaction pathways for CO 2 hydrogenation: surface redox pathway, formate pathway and carboxylate pathway. Based on the results of the DRIFTS experiment, we observed that gas-phase CO bands (2111 cm −1 and 2176 cm −1 ) appeared at temperatures above 250 °C, and the bands gradually became stronger as the temperature increased.…”

Section: Resultsmentioning

confidence: 99%

Slag-based geopolymer microsphere-supported Cu: a low-cost and sustainable catalyst for CO₂ hydrogenation

Deng

Quan

et al. 2022

Sustainable Energy Fuels

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Mechanistic insight into the catalytically active phase of CO2 hydrogenation on Cu/ZnO catalyst

Cited by 20 publications

References 63 publications

Cesium-Induced Active Sites for C–C Coupling and Ethanol Synthesis from CO₂ Hydrogenation on Cu/ZnO(0001̅) Surfaces

Cesium-Induced Active Sites for C–C Coupling and Ethanol Synthesis from CO₂ Hydrogenation on Cu/ZnO(0001̅) Surfaces

H₂ Activation on Pristine and Substitutional ZnO(101̅0) and Cr₂O₃(001) Surfaces by Density Functional Theory Calculations

Slag-based geopolymer microsphere-supported Cu: a low-cost and sustainable catalyst for CO₂ hydrogenation

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Mechanistic insight into the catalytically active phase of CO2 hydrogenation on Cu/ZnO catalyst

Cited by 20 publications

References 63 publications

Cesium-Induced Active Sites for C–C Coupling and Ethanol Synthesis from CO2 Hydrogenation on Cu/ZnO(0001̅) Surfaces

Cesium-Induced Active Sites for C–C Coupling and Ethanol Synthesis from CO2 Hydrogenation on Cu/ZnO(0001̅) Surfaces

H2 Activation on Pristine and Substitutional ZnO(101̅0) and Cr2O3(001) Surfaces by Density Functional Theory Calculations

Slag-based geopolymer microsphere-supported Cu: a low-cost and sustainable catalyst for CO2 hydrogenation

Contact Info

Product

Resources

About

Cesium-Induced Active Sites for C–C Coupling and Ethanol Synthesis from CO₂ Hydrogenation on Cu/ZnO(0001̅) Surfaces

Cesium-Induced Active Sites for C–C Coupling and Ethanol Synthesis from CO₂ Hydrogenation on Cu/ZnO(0001̅) Surfaces

H₂ Activation on Pristine and Substitutional ZnO(101̅0) and Cr₂O₃(001) Surfaces by Density Functional Theory Calculations

Slag-based geopolymer microsphere-supported Cu: a low-cost and sustainable catalyst for CO₂ hydrogenation