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

H 2 O 2 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 WO 3 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 WO 3 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 H 2 O 2 production from water.