Metal-doped black In2O3 for atmospheric-pressure photothermal CO2 reduction with high efficiency and selectivity†

Abstract

Indium oxide is widely used in the photothermal catalytic reduction of CO₂. However, the high bandgap and relative low CO₂ adsorption capacity limit its application. Herein, we report a simple and cost-effective strategy to modify In₂O₃ with hydrogen treatment and Cu doping to form a Cu–In₂O_{3− x} catalyst with a lower bandgap and enhanced CO₂ adsorption properties. The catalyst can absorb more visible light and effectively reduce the activation energy of the intermediate in the CO₂ reduction route, thus demonstrating superior performance in the photothermal catalytic reduction of CO₂. Moreover, the Cu–In₂O_{3− x} catalyst can maintain almost 100% product selectivity over a wide range of reaction conditions and reaches the highest yield compared to other doping noble metals (Ru, Pt, and Rh). This catalyst synthesis strategy provides practical application prospects for CO green manufacturing, as well as inspiration for the performance improvement of other catalytic materials.