Selective Photocatalytic Oxidation of Methane to Oxygenates over Cu–W–TiO2 with Significant Carrier Traps

Direct selective methane photooxidation to liquid oxygenates with high productivity and selectivity under mild reaction conditions is highly urgent but remains challenging. Herein, a Cu and W codoped TiO2 (Cu–W–TiO2) photocatalyst was fabricated to enable aerobic oxidation of methane into oxygenates with limited formation of CO2 under ambient temperature. A high oxygenate productivity of 34.5 mmol g–1 with a remarkable selectivity of 97.1% was achieved over the Cu–W–TiO2 photocatalyst. Based on structural characterizations and mechanism studies, it was suggested that the Cu species acted as hole traps, while oxygen vacancies and the W6+-dopant state worked as electron traps. The inhibited recombination of photogenerated carriers contributed to enhanced photocatalytic efficiency. The modulated electronic and band structure promoted the activation of methane and hindered the overoxidation of oxygenates.