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

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 H 2 -TPR, XRD, in-situ XPS, AAS, CO 2 -TPD, and H 2 -TPD. The characterizations showed that the oxygen vacancies and active Cu 0 species as active sites were formed in the CeCu catalysts by the H 2 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 CO 2 and H 2 molecules on the corresponding CeCu catalysts. The Ce 1.1 Cu 1 catalyst demonstrated high stability and the highest CO 2 conversion rate in the RWGS reaction, reaching 1.38 mmol g cat −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 CO 2 conversion, 100% CO selectivity, and high stability.