Redox-Mediated Interfacial Restructuring of Supported In2O3 to Drive CO2 Hydrogenation to Methanol

Abstract

The successful hydrogenative conversion of CO₂ to methanol necessitates effective strategies to finely tune the interfacial structures for optimal performance. Herein, we present a redox-mediated interfacial restructuring approach adopted to enhance the catalytic activity of supported In₂O₃ for efficient CO₂-to-methanol conversion. A sequential H₂/O₂ reduction–reoxidation treatment was applied to markedly alter the interfacial architecture and electronic properties of In₂O₃, resulting in an oxygen vacancy site (OV)-abundant In₂O_3–x patch-like overlayer on monoclinic ZrO₂. This architectural optimization maximizes the availability of active sites and promotes heterolytic H₂ dissociation along with associative CO₂ activation at the interfacial In–O–Zr sites, enabling highly effective catalysts that remain active while being stable against structural reconstruction during CO₂ hydrogenation to methanol. Additionally, this redox treatment proved to be effective in restoring activity in deactivated 15In/Zr catalysts made solely via simple impregnation, while also enhancing their inherent stability. This work emphasizes the effectiveness of this method in enhancing In₂O₃ catalyst performance, while underscoring the critical role of key evaluation metrics (KEMs), including the dispersion degree, anti-overreduction factor, OV density, relative abundance of interfacial In–O–Zr sites, and In average valence state, in advancing the development of In-based catalysts for methanol synthesis. These results set new prospects for developing efficient and stable heterogeneous catalysts to facilitate essential chemical synthesis under CO₂ utilization conditions.