A strong metal-support interaction strategy for enhanced proton-coupled electron transfer and promoted photocatalytic H2O2 production in pure water

Proton-coupled electron transfer (PCET) is a key factor in determining the H 2 O 2 production efficiency from oxygen reduction reaction (ORR) or direct H 2 /O 2 reaction, which usually requires the aid of proton donors including alcohols. Here, we report a strong metal-support interaction (SMSI) strategy to facilitate the PCET process of a typical Pd/TiO 2 photocatalyst for photocatalytic ORR into H 2 O 2 production in pure water. Compared to conventional Pd/TiO 2 photocatalysts, the Pd/TiO 2 photocatalyst with SMSI between Pd and TiO 2 (Pd/TiO 2 -850H) promotes photocatalytic H 2 O 2 production in pure water by 4.21-fold, which can be ascribed to that the SMSI simultaneously promotes the H 2 O dissociation and the photogenerated charge transfer from TiO 2 to Pd catalyst, enabling highly efficient proton transfer to be participated into converting •O 2 - to H 2 O 2 . Moreover, the formation of TiO 2-x overlayer caused by SMSI suppresses the H 2 O 2 decomposition and stabilizes Pd NPs, finally achieving an H 2 O 2 production rate of 4.10 mmol g −1 h −1 , which surpasses most metal/TiO 2 photocatalytic system.