Synergistic integration of bimetallic PtCu alloy modulating proton supply for efficient artificial photosynthesis of methanol.

Photocatalytic CO2 reduction with H2O into valuable solar fuels is a huge potential to alleviate carbon emissions and energy issues. However, selective photocatalytic CO2 reduction with H2O into desired chemicals is still a grand challenge owing to the unfavorable kinetics of multistep proton-coupled electrons. Herein, we employed a facile photo-deposition strategy to load Pt-Cu alloy over BiOBr1-xClx (BOBC) for CO2 photoreduction with H2O as a proton donor. The optimal Pt-Cu/BOBC with Pt-Cu pair sites exhibited a remarkable performance of CO2 photoreduction yielding CH3OH of 16.52 μmol·g-1·h-1 with 97.14 % electron-based selectivity. The experimental and theoretical analysis revealed the synergistic effect of Pt-Cu pair sites in BOBC, which enabled Pt to promote the formation of protons from dissociated H2O while Cu accelerate the protonation of CO2, thus advancing the highly selective production of CH3OH. This work highlighted the role of proton supply from H2O oxidation to promote the kinetics of CO2 protonation during photocatalytic reaction.