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, CO 2) 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-WO 3-x) was constructed to successfully realize the one-step photocatalytic conversion of CH 4 to CH 3 COOH without addition of carbonyl species. Chlorine radicals and hydroxyl radicals could be produced simultaneously under light irradiation over Ag/AgCl. Specifically, CH 4 could undergo the hydrogen atom transfer reaction with chlorine radicals to produce methyl species, and hydroxyl radicals could mineralize CH 4 to produce carbonyl species. After further combining WO 3 − x , carbon-carbon coupling reaction between carbonyl and methyl species occurred to effectively produce CH 3 COOH (188.5 μmol·g cat −1·h−1). This work provides a new prospect of designing photocatalytic system to realize CH 4 conversion to C 2 products. [Display omitted] • One-step conversion of CH 4 to CH 3 COOH is achieved over the photocatalyst of Ag/AgCl-WO 3−x. • ·Cl and ·OH produced over Ag/AgCl contributed to obtain active methyl and carbonyl species, respectively. • WO 3−x enables the C-C coupling reaction between methyl and carbonyl species. [ABSTRACT FROM AUTHOR]