Cu single atoms on defective carbon nitride for photocatalytic oxidation of methane to methanol with selectivity over 92%

The photocatalytic oxidation of methane to methanol using molecule oxygen directly is an attractive catalytic reaction, but designing catalysts to avoid over-oxidation remains a significant challenge. Herein, Cu single-atom anchored on the defective carbon nitride structure (Cu SA/Def-CN) is designed for selective photocatalytic oxidation of methane into methanol using O 2 under mild conditions. The Cu SA/Def-CN catalyst exhibits a high methanol selectivity of 92.8% under optimized conditions. Mechanistic studies reveal a synergistic effect between Def-CN and Cu SA, where Def-CN is responsible for the in-situ generation of hydrogen peroxide, which is subsequently decomposed by the Cu SA sites to produce ·OH radicals that play a key role in the rate-determining step of methane activation to form methanol. Additionally, the presence of Cu SA not only enhances the electron-hole separation efficiency and improves the transfer of the photo-generated charges, but also increases the number of active sites for methane adsorption and activation. These insights provide valuable guidance for designing efficient catalysts for the highly selective photocatalytic oxidation of methane to methanol.