Hybrid MOF Template-Directed Construction of Hollow-Structured In 2 O 3 @ZrO 2 Heterostructure for Enhancing Hydrogenation of CO 2 to Methanol.

Direct hydrogenation of CO ₂  to methanol using green hydrogen has emerged as a promising method for carbon neutrality, but qualifying catalysts represent a grand challenge. In ₂ O ₃ /ZrO ₂  catalyst has been extensively applied in methanol synthesis due to its superior activity; however, the electronic effect by strong oxides-support interactions between In ₂ O ₃  and ZrO ₂  at the In ₂ O ₃ /ZrO ₂  interface is poorly understood. In this work, abundant In ₂ O ₃ /ZrO ₂  heterointerfaces are engineered in a hollow-structured In ₂ O ₃ @ZrO ₂  heterostructure through a facile pyrolysis of a hybrid metal-organic framework precursor MIL-68@UiO-66. Owing to well-defined In ₂ O ₃ /ZrO ₂  heterointerfaces, the resultant In ₂ O ₃ @ZrO ₂  exhibits superior activity and stability toward CO ₂  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 g _MeOH  g _cat ^-1  h ^-1 . Extensive characterization demonstrates that there is a strong correlation between the strong electronic In ₂ O ₃ -ZrO ₂  interaction and catalytic selectivity. At In ₂ O ₃ /ZrO ₂  heterointerfaces, the electron tends to transfer from ZrO ₂  to In ₂ O ₃  surface, which facilitates H ₂  dissociation and the hydrogenation of formate (HCOO*) and methoxy (CH ₃ O*) species to methanol. This study provides an insight into the In ₂ O ₃ -based catalysts and offers appealing opportunities for developing heterostructured CO ₂  hydrogenation catalysts with excellent activity.
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