Cobalt-Phosphate (Co-Pi)-Modified WO3 Photoanodes for Performance-Enhanced Photoelectrochemical Wastewater Degradation

Abstract

Photocatalytic technology, with features of wide applicability, mild reaction conditions and sunlight availability, satisfies the requirements of “green chemistry”. As the star photoanode material for photoelectrochemical catalysis, WO3 has a suitable band gap of 2.8 eV and a strong oxidation capacity, as well as displaying great potential in organic wastewater degradation. However, its performance is usually hindered by competition with water oxidation to generate peroxides, rapid charge complexation caused by surface defect sites, and so on. Herein, WO3 films modified with cobalt–phosphate (Co-Pi/WO3) film were prepared and involved in photocatalytic organic wastewater degradation. A degradation rate constant of 0.63311 h−1 was obtained for Co-Pi/WO3, which was much higher than that of WO3, 10.23 times that of direct photocatalysis (DP) and 23.99 times that of electrocatalysis (EC). After three cycles of degradation, the film can maintain a relatively good level of stability and a degradation efficiency of 93.79%.