In situ tuning of electronic structure of catalysts using controllable hydrogen spillover for enhanced selectivity

Abstract

Abstract In situ tuning of the electronic structure of active sites is a long-standing challenge. Herein, we propose a strategy by controlling the hydrogen spillover distance to in situ tune the electronic structure. The strategy is demonstrated to be feasible with the assistance of CoO x /Al 2 O 3 /Pt catalysts prepared by atomic layer deposition in which CoO x and Pt nanoparticles are separated by hollow Al 2 O 3 nanotubes. The strength of hydrogen spillover from Pt to CoO x can be precisely tailored by varying the Al 2 O 3 thickness. Using CoO x /Al 2 O 3 catalyzed styrene epoxidation as an example, the CoO x /Al 2 O 3 /Pt with 7 nm Al 2 O 3 layer exhibits greatly enhanced selectivity (from 74.3% to 94.8%) when H 2 is added. The enhanced selectivity is attributed to the introduction of controllable hydrogen spillover, resulting in the reduction of CoO x during the reaction. Our method is also effective for the epoxidation of styrene derivatives. We anticipate this method is a general strategy for other reactions.