Low-Work Function Metals Boost Selective and Fast Scission of Methanol C–H Bonds

Photocatalytic production of chemicals and fuels with H2 evolution has raised broad interest due to the carbon emission-free feature. In this context, selective and fast scission of methanol C–H bonds for coproduction of H2 and ethylene glycol (EG) over metal–semiconductor composites remains to be achieved. Here, we demonstrate that indium nanoparticles (In NPs) with a low work function (<4.3 eV) increase the selectivity and activity of ZnIn2S4 for the scission of methanol C–H bonds. By accepting electrons from In NPs, ZnIn2S4 with enriched electrons tends to activate the C–H bond instead of the O–H bond. Besides, a relatively strong built-in field is formed between In NPs and the support, which facilitates photogenerated electron transfer to In NPs for H2 evolution. Consequently, 84% selectivity of EG is obtained, and the apparent quantum yields (365 nm) of EG and H2 reach 15.6 and 27.0%, respectively. This concept of methanol C–H bond scission boosted by low-work function metal is also proved by immobilizing In, Cd, and Bi to ZnS, resulting in up to 89% selectivity of EG.