Efficient methane production from photocatalytic CO2 reduction by InCu0.05Co0.05Ox: The synergistic effect of Co and Cu

Abstract

Photocatalytic reduction of CO2 to methane (CH4) is a promising strategy to address CO2 emissions and energy scarcity. However, low efficiency limits its practical application. This study presents a bimetallic co-doping strategy using Cu and Co to enhance the photocatalytic performance of the In2O3 catalyst. The InCu0.05Co0.05Ox (InCuCo) catalyst demonstrated a CH4 yield of 22.3 µmol·g−1·h−1, outperforming In2O3 (8.8 µmol·g−1·h−1), InCu (14.5 µmol·g-1·h−1), and InCo (18.0 µmol·g-1·h−1). This remarkable improvement highlights the synergistic effects of Cu and Co in the In2O3 catalyst. Characterizations and density functional theory (DFT) calculations revealed that Co doping narrows the bandgap of the catalyst, enhancing light utilization, while Cu adjusts the energy band positions and improves CO2 adsorption. Consequently, the InCuCo catalyst significantly enhances the photocatalytic reduction of CO2–CH4, offering remarkable activity and stability. These results provide new insights into CO2 photoreduction to CH4, facilitating further practical applications.