Establishing an Optimal Metal–Support Interaction Regime in Cu/In2O3 Catalysts for Stable CO2 Hydrogenation to Methanol

Abstract

Balancing metal–support interactions (MSI) is critical for achieving both activity and stability in Cu/In2O3 catalysts for CO2 hydrogenation. Herein, a metal–organic framework (MOF)-templated precursor strategy is employed to regulate the initial spatial distribution of Cu and In species, thereby generating Cu/In2O3 catalysts with distinct MSI regimes. Among the three MSI regimes constructed, the MIL-68(In)-derived catalyst exhibits a moderated MSI that provides a favorable balance between interfacial activation and structural stability. The MOF-derived catalyst suppresses Cu–In alloy formation while promoting oxygen-vacancy generation and maintaining a balanced Cu0/Cuδ+ equilibrium. The MIL-derived catalyst achieves a methanol space–time yield of 0.374 gMeOH·gcat–1·h–1 at 300 °C with stable performance. In situ DRIFTS measurements indicate that moderated MSI accelerates the conversion of formate intermediates into methoxy species, while DFT calculations provide atomistic insight into MSI-dependent interfacial charge transfer and H2/CO2 adsorption. In contrast, excessively strong MSI drives irreversible Cu–In alloy formation, whereas weak MSI leads to insufficient interfacial activation and particle sintering. These findings establish an optimal MSI regime for balancing interfacial reactivity and structural durability and highlight MOF-templated precursor engineering as an effective strategy for designing robust Cu/In2O3 catalysts for CO2 hydrogenation.