Highly active sunlight-driven CO[formula omitted] methanation catalyst: Design of the interfacial structure

Abstract

A kind of nickel catalyst supported on the defect-rich ZrO2 (5Ni/ZrO2-0.5R) was developed, which exhibited 66∼70% of CO2 conversion accompanied with more than 99% CH4 selectivity in the range of 300∼380 °C. Thus, the green and sustainable CO2 methanation over 5Ni/ZrO2-0.5R can be achieved smoothly in a photo-thermal transform tube that can provide temperature range of 300∼400 °C under sun. A combination of control experiments, in-situ spectroscopy analyses and characterizations provides an insight into the active sites at the interface between nickel and oxygen vacancy(Ov)-rich ZrO2. The presence of sodium and oxygen vacancies promotes the dissociative adsorption of CO2 so that change the mechanism of CO2 methanation from formate-hydrogenation pathway into CO-hydrogenation pathway. Further theoretical calculations indicate that the Zr4+-Ov structures leads to significantly improved Ni dispersion and the Na+-Ov-Ni sites drive the CO2 methanation through a CO-hydrogenation mechanism.