Support-Dependent Cu–In Bimetallic Catalysts for Tailoring the Activity of Reverse Water Gas Shift Reaction

Cu-based bimetallic catalysts have attracted great attention for the reverse water gas shift (RWGS) reaction due to their high activity and selectivity. This work reports the application of Cu–In bimetallic catalysts for the RWGS reaction and demonstrates that the promotion effect of In on Cu is support sensitive. The Cu–In/ZrO 2 catalyst exhibited significantly higher CO 2 conversion than the Cu/ZrO 2 catalyst, whereas the CO 2 conversion over Cu–In/CeO 2 was much lower than that of Cu/CeO 2 . The reasons of the support-dependent RWGS activity was revealed by systematic characterizations. On the ZrO 2 support, Cu and In formed Cu–In alloys and promoted the activation of CO 2 by the oxygen vacancies from partially reduced In 2 O 3 . On the CeO 2 support, Cu and In were in the form of metallic Cu and In 2 O 3, respectively. The dispersion of Cu and the formation of oxygen vacancies on CeO 2 were obstructed by the introduction of In, leading to decreased RWGS activity. Among these catalysts, Cu/CeO 2 showed the best RWGS activity because of the strong CO 2 activation ability of the partially reduced CeO 2 support and the highly active Cu/CeO 2– x interfaces. These results provide new insights into the design and understanding of supported bimetallic catalysts for CO 2 hydrogenation.