Synergistic effect of F doping and WO3 loading on electrocatalytic oxygen evolution

Abstract

Electrochemical oxygen evolution reaction (OER) is an important anodic semi-reaction for energy storage and conversion. In this work, Perfluorooctanoic acid (PFOA), an aqueous pollutant, is degraded into F-containing fragments and captured to prepare ultrasmall WO3 decorated F-doped graphite sheets (WO3@F-GS) via a plasma-induced assembly method. WO3@F0.1-GS achieves a low overpotential of 298 mV and Tafel slope of 77.6 mV dec-1, as low as that of RuO2. Meanwhile, WO3@F0.1-GS exhibits good stability in both OER and overall water splitting in 1 M KOH. The synergistic effect of WO3 and F enhances the electrocatalytic performance. Density functional theory calculations prove W4+ coordinates with F-doping resulting in enhanced adsorption of OH– and decreased energy barrier of OH deprotonation, leading good activity. The steric hindrance of F and WO3 loading hinder the stacking of graphitic layers and improve the stability. This work not only provides a mild synthesis strategy of F-doping, but also provides a novel reutilization approach for fluoride waste.