CeCu composite catalyst for CO synthesis by reverse water–gas shift reaction: Effect of Ce/Cu mole ratio. (October 2017)

• Record Type: Journal Article
• Authors: Zhou, Guilin; Dai, Bican; Xie, Hongmei; Zhang, Guizhi; Xiong, Kun; Zheng, Xuxu
• Is Part Of: Journal of CO₂ utilization. Volume 21(2017)
• Page Start: 292
• Page End: 301
• Publication Date: 2017-10
• Subjects: RWGS reaction -- CO2 -- CeCu composite catalyst -- CO -- Resource utilization; Carbon dioxide -- Periodicals; Carbon dioxide -- Environmental aspects -- Periodicals; Carbon dioxide mitigation -- Periodicals; Carbon dioxide; Carbon dioxide -- Environmental aspects; Carbon dioxide mitigation; Periodicals; 628.53205
• DOI: 10.1016/j.jcou.2017.07.004
• Languages: English
• ISSNs: 2212-9820

Abstract

Graphical abstract: Ce x Cu y O precursors can be effectively reduced at 400 °C because of the interactions of CuO with CeO2 to form surface oxygen vacancies and active Cu species. The synergistic effect of the surface oxygen vacancies with active Cu 0 species can be realized, and the active Cu 0 species can be stabilized because of the existence of Ce 3+ -□-Cu 0 (□: oxygen vacancy) structure. The existence of Ce 3+ -□-Cu 0 structure in the Ce x Cu y catalyst can improve the electrons transfer to Ce from Cu to increase an electron-deficient state of the Cu species, which can enhance the adsorption performance of reactants CO2 and H2 molecules on the Ce x Cu y catalysts. Consequently, the CO2 conversion on the Ce1.1 Cu1 catalyst is significantly superior to those of the pure CeO2-δ and pure Cu 0 . And, the Ce1.1 Cu1 catalyst can maintain a long-time stability for the CO2 RWGS reaction. Highlights: The CeCu composite catalysts were prepared by hard template method for the RWGS reaction. Active Cu 0 species and oxygen vacancies produced as confirmed via XRD and in situ XPS. The electronic effect boosted the adsorption performance of catalysts for CO2 and H2 molecules. The synergistic effect between active Cu 0 and oxygen vacancies contributed to the high RWGS activity. Abstract: In this study, CeCu composite catalysts with different Ce/Cu mole ratios were prepared by a hard-template, and their performances in the reverse water–gas shift (RWGS) reaction were investigated. The catalysts were characterized using H2 -TPR, XRD, in-situ XPS, AAS, CO2 -TPD, and H2 -TPD. The characterizations showed that the oxygen vacancies and active Cu 0 species as active sites were formed in the CeCu catalysts by the H2 reduction at 400 °C. The synergistic effect of the surface oxygen vacancies and active Cu 0 species enhanced catalytic activity of the studied CeCu composite catalysts. The electronic effect between Cu and Ce species boosted the adsorption and activation performances of the reactant CO2 and H2 molecules on the corresponding CeCu catalysts. The Ce1.1 Cu1 catalyst demonstrated high stability and the highest CO2 conversion rate in the RWGS reaction, reaching 1.38 mmol gcat −1 min −1 at 400 °C. Its excellent catalytic performance in the RWGS reaction was related to the complete synergistic interaction between the active species via Ce 3+ -□-Cu 0 (□: oxygen vacancy). A CeCu composite material is a superior catalyst for the RWGS reaction because of its high CO2 conversion, 100% CO selectivity, and high stability.