Boosting 2 e- water oxidation reaction on WO3 by F modification and revealing the mechanism by probing interfacial water structure

Abstract

H2O2 production by 2 electron water oxidation reaction (2e- WOR) is a promising approach, but still lacks mechanistic studies especially from a dynamic point of view. The interfacial water behavior on the solid/liquid interface is believed to play a crucial role in WOR activity. Here, F modification was used to accommodate the structure and dynamic process of interfacial water on WO3 surface and boost the 2e- WOR activity. Electrochemical measurement, Raman spectra and computational techniques were used to investigate the mechanism. F modification was proved to guide the dipole moments of interfacial water molecules towards WO3 surface, meaning more difficult to flip interfacial water molecules to perform the first step of WOR, in turn resulting in easy desorption of HO* and O-O*, thus benefiting for 2 e- WOR. This work paves a novel insight to understand mechanism of 2 e- WOR and rationally design the electrocatalysts for H2O2 production from water.