Structure Sensitivity of an Atomic Co-Promoted In<sub>2</sub>O<sub>3</sub> Catalyst toward CO<sub>2</sub> Hydrogenation to Methanol
Shanshan Dang, Xiaoya Ding, Jinying Li, Junchao Chang, Zhenzhou Zhang, Peng Gao, Weifeng Tu, Yi‐Fan Han
Abstract
Deciphering the relationship between the active site structure and the CO 2 hydrogenation to methanol mechanism over In 2 O 3 -supported high-dispersed metal catalysts faces great challenges. Herein, by using atomically dispersed Co@In 2 O 3 with the main exposed facet as a model catalyst, Co@In 2 O 3 (111) and Co@In 2 O 3 (012) are prepared to investigate the structure sensitivity toward CO 2 hydrogenation. Co@In 2 O 3 (012) exhibits higher methanol selectivity (78.0%) with a prominent durability within a 100 h time-on-stream test at 280 °C and 9000 mL g –1 h –1, while Co@In 2 O 3 (111) exhibits a mediocre selectivity of methanol (64.7%) but relatively higher CO 2 conversion. Experiments and theoretical simulations substantiate that the hydrogenation of CO 2 to methanol follows the formate pathway over both catalysts. The oxygen vacancy sites on the Co@In 2 O 3 (012) surface can more effectively stabilize the intermediates of the CO 2 hydrogenation reaction and exhibit a lower reaction energy barrier of the rate-determining step about the conversion of HCOO* to H 2 COO*, achieving a higher methanol selectivity. This study might be of great aid in providing comprehensive insight into the structure–activity relationship of Co@In 2 O 3 catalysts and the design of robust catalysts for highly selective hydrogenation of CO 2 to methanol.