Surface States of Mo-Doped BiVO4 Nanoparticle-Based Photoanodes for Photoelectrochemical Degradation of Chloramphenicol

Mo-doped BiVO4 (Mo-BiVO4) nanoparticle-based photoanodes were fabricated using an electrodeposition–calcination method to investigate the influence of Mo doping on the surface states (SS) for the photoelectrocatalytic degradation performance of chloramphenicol (CAP) in water. The characterization results show that the prepared samples were nanostructured BiVO4. Mo doping with a low concentration has a negligible effect on the surface nanomorphology, crystal structure, and light absorption characteristics. CAP as an efficient organic scavenger can undergo degradation via the photoelectron trapping/detrapping process of the V5+/V4+ redox system under illumination. The photoelectron trapping process of V5+ to V4+ exhibited an increase and then a decrease with increasing Mo doping concentrations. The introduction of suitable Mo into the BiVO4 can tune the photoelectron trapping process to form the surface states for adsorbing CAP (SSCAP). Furthermore, Mo doping produces more oxygen vacancies (Vo) on the electrode surface, which are in favor of trapping photogenerated holes, thereby promoting the charge transfer efficiency at the semiconductor–electrolyte interface (SEI). These multiple effects process the highest charge transfer efficiency (reaching 96%) for CAP degradation when the Mo doping content is 1.07 wt %. This work gives a further understanding of the enhancement of photoelectrocatalytic degradation performance caused by Mo doping in the field of charge transfer at SEI.