Direct oxidation of methane into methanol, a 100% atom-economy process, is challenging due to the difficulty in activating methane and preventing over-oxidation of methanol. This study reports that water facilitates the mild oxidation of methane to methanol with >99% selectivity over Au single atoms on black phosphorus (Au₁/BP) nanosheets under light irradiation. The Au₁/BP nanosheets exhibit high mass activity and a low activation energy. Mechanistic studies suggest water assists in O₂ activation, generating hydroxyl groups and •OH radicals. These radicals then react with methane at Au single atoms, leading to methanol formation. Water's complete recycling makes it function as a catalyst.

Laihao Luo, Jie Luo, Hongliang Li, Fangning Ren, Yifei Zhang, Andong Liu, Wei-Xue Li, Jie Zeng