Multi-radicals mediated one-step conversion of methane to acetic acid via photocatalysis

One-step photocatalytic methane conversion to acetic acid possesses high economic and academic value, and carbonyl species (CO, CO2) are usually necessary to be introduced into the reaction system to realize the carbon-carbon coupling reaction, which requires high energy input. In this work, a composite photocatalyst (Ag/AgCl-WO3-x) was constructed to successfully realize the one-step photocatalytic conversion of CH4 to CH3COOH without addition of carbonyl species. Chlorine radicals and hydroxyl radicals could be produced simultaneously under light irradiation over Ag/AgCl. Specifically, CH4 could undergo the hydrogen atom transfer reaction with chlorine radicals to produce methyl species, and hydroxyl radicals could mineralize CH4 to produce carbonyl species. After further combining WO3−x, carbon-carbon coupling reaction between carbonyl and methyl species occurred to effectively produce CH3COOH (188.5 μmol·gcat−1·h−1). This work provides a new prospect of designing photocatalytic system to realize CH4 conversion to C2 products.