Core-shell Ni/SiO2@ZrO2 catalyst for highly selective CO2 conversion accompanied by enhancing reaction stability.

CO2 RWGS reaction was considered to be a promising process for carbon dioxide conversion, however it retained a big challenge owing to methanation and metal sintering. Therefore, it was desperately needed to devise highly selective and stable catalyst. Herein, core-shell Ni/SiO2@ZrO2 catalyst was successfully prepared via a combination of the wet impregnation and in-situ hydrothermal synthesis method, with ZrO2 as the coating shell. The optimized Ni/SiO2@4ZrO2 catalyst possessed enhanced metal-support interaction and rich oxygen vacancies as well as abundant medium-strength CO2 adsorption sites. As a result, under the GHSV of 120000 mL/g·h and 150000 mL/g·h, Ni/SiO2@4ZrO2 displayed a considerable hydrogenation activity and significantly higher selectivity to CO, compared with the Ni/SiO2 catalyst as a reference. During stability tests, Ni/SiO2@4ZrO2 also showed a superior catalytic stability with a steady 100 % CO selectivity, carried out at 600 °C for 72 h. This work provided a novel strategy of designing a core-shell catalyst for CO2 RWGS reaction, and was expected to be put into use in other multiphase reaction process.