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 3.0 MPa with a methanol space-time yield of up to 0.29 gMeOH  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*) and methoxy (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.