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

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–In2O3−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–In2O3−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.