Enhancement of hollow Ni/CeO2-Co3O4 for CO2 methanation: From CO2 adsorption and activation by synergistic effects

CO2 absorption and activation play key roles in the process of CO2 methanation, but revealing the mechanism and synergistic effects are still challenges, especially in some complicated routes. Herein, an optimized hollow Ni/CeO2-Co3O4 catalyst is shown to be capable of CO2 absorption and activation, the performance could be attributed to the strong synergistic effects among each component. In addition, the respective role was verified that the Co3O4 and CeO2 contributed to the CO2 adsorption and subsequently coupled with Ni for CO2 activation. Furthermore, in-situ DRIFTS were used to demonstrate the hydrogenation mechanisms, and the promotion of CO2 absorption and CH4 selectivity was confirmed in Ni/CeO2-Co3O4. The DFT results verified the synergistic effects of the established catalysts, which could also be a universal strategy for the catalysts designation.