MoS2-confined Rh-Zn atomic pair boosts photo-driven methane carbonylation to acetic acid

Direct carbonylation of CH4 to CH3COOH provides a promising pathway for upgrading of natural gas to transportable liquid chemicals, in which high-efficiency CH4 activation and controllable C–C coupling are both critical but challenging. Herein, we report that highly efficient photo-driven carbonylation of CH4 with CO and O2 to CH3COOH is achieved over MoS2-confined Rh-Zn atomic-pair in conjunction with TiO2. It delivers a high CH3COOH productivity of 152.0 μmol gcat.−1 h−1 and turnover frequency of 62.0 h−1 with a superior selectivity of 96.5%, outperforming previous photocatalytic CH4 carbonylation processes. Mechanistic investigations disclose the key effect of Rh-Zn synergy in combination with photo-excited electrons from TiO2 for CH3COOH formation. The active OH species produced from O2 photoreduction on the Zn site through proton-coupled electron transfer promotes CH4 dissociation to CH3 species, which then facilely couples with adsorbed CO on the adjacent Rh site forming the key CH3CO intermediate for CH3COOH formation. The authors report a catalyst featuring Rh-Zn dual sites in a MoS2 lattice integrated with TiO2 for the photocatalytic carbonylation of CH4 with CO and O2 to CH3COOH with a high productivity of 152.0 μmol gcat.−1 h−1 and selectivity of 96.5%.