Influence of Vanadate Structure on Electrochemical Surface Reconstruction and OER Performance of CoV2O6 and Co3V2O8

Underlying factors responsible for superior phase-dependent electrocatalytic OER activity of crystalline Co-vanadates are investigated. Previous reports on Co-vanadates ascribed activity differences to optimal metal-oxygen bond strength. In contrast, we found etching of vanadate from precatalyst during electrochemical activation to be the primary contributor. The resulting higher surface reconstruction exposes a higher number of catalytically active cobalt sites that otherwise lay inactive due to their position in bulk. Co-vanadates with polymeric vanadates (CoV2O6) showed better OER over monomeric orthovana-dates (Co3V2O8) due to higher vanadate etching. Further, this work validates that etching can happen even from lattice positions, where bonding between constituents is strong.

Automated summary

The factors contributing to the superior phase-dependent electrocatalytic OER activity of crystalline Co-vanadates were investigated. It was found that etching of vanadate from the precatalyst during electrochemical activation significantly contributes to the increased catalytic activity. Co-vanadates with polymeric vanadates showed better performance than monomeric orthovanadates due to higher vanadate etching, highlighting the importance of surface reconstruction in exposing more catalytically active sites.