Ternary synergistic interaction of Cu-ZnO-ZrO2 promoting CO2 hydrogenation to methanol

Abstract

The effectiveness of Cu-ZnO-ZrO 2 (CZZ) catalysts is largely influenced by the cooperative interaction between the three components. This study involved the preparation of various CZZ catalysts by altering the molar ratio of Cu/Zn to adjust the ternary synergy of Cu-ZnO-ZrO 2 , with the aim of examining its impact on the hydrogenation of CO 2 to methanol. The characterization results including XRD, Raman, TEM, SEM, and XPS confirmed that the formed CuZn alloy over catalyst surface and the intimate Cu-ZnO x interface were the main reasons for the good activity. In-situ DRIFTS showed that CO 2 hydrogenation primarily followed the formate pathway on CZZ catalysts. The interactions between ZnO and ZrO 2 greatly enhanced the generation of oxygen vacancies, improved the adsorption and activation of CO 2 , and further stabilized the formate species which formed on ZnO-ZrO 2 interfaces. Copper species played a vital role in H 2 dissociation and formate intermediates to methoxide. The synergistic interaction of ternary components cooperatively catalyzed CO 2 hydrogenation to methanol. • CuZn alloy and the intimate Cu-ZnO x interface over Cu-ZnO-ZrO 2 catalyst were the main reasons for the good activity. • The relatively high content of Cu + showed higher activity. • The CO 2 hydrogenation to methanol over Cu-ZnO-ZrO 2 followed the formate intermediate pathway. • Interactions between ZnO and ZrO 2 enhanced the generation of oxygen vacancies, and stabilized the formate species. • Copper species played a vital role in H 2 dissociation and promoted formate intermediates to methoxide.