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 InCu_0.05Co_0.05O_x (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.