Hybrid MOF Template-Directed Construction of Hollow-Structured In2 O3 @ZrO2 Heterostructure for Enhancing Hydrogenation of CO2 to Methanol.

Abstract

Direct hydrogenation of CO2 to methanol using green hydrogen has emerged as a promising method for carbon neutrality, but qualifying catalysts represent a grand challenge. In2 O3 /ZrO2 catalyst has been extensively applied in methanol synthesis due to its superior activity; however, the electronic effect by strong oxides-support interactions between In2 O3 and ZrO2 at the In2 O3 /ZrO2 interface is poorly understood. In this work, abundant In2 O3 /ZrO2 heterointerfaces are engineered in a hollow-structured In2 O3 @ZrO2 heterostructure through a facile pyrolysis of a hybrid metal-organic framework precursor MIL-68@UiO-66. Owing to well-defined In2 O3 /ZrO2 heterointerfaces, the resultant In2 O3 @ZrO2 exhibits superior activity and stability toward CO2 hydrogenation to methanol, which can afford a high methanol selectivity of 84.6% at a conversion of 10.4% at 290°C, and 3.0MPa with a methanol space-time yield of up to 0.29gMeOH gcat -1 h-1 . Extensive characterization demonstrates that there is a strong correlation between the strong electronic In2 O3 -ZrO2 interaction and catalytic selectivity. At In2 O3 /ZrO2 heterointerfaces, the electron tends to transfer from ZrO2 to In2 O3 surface, which facilitates H2 dissociation and the hydrogenation of formate (HCOO*) andmethoxy (CH3 O*) species to methanol. This study provides an insight into the In2 O3 -based catalysts and offers appealing opportunities for developing heterostructured CO2 hydrogenation catalysts with excellent activity.