BiVO4@PDA/TiO2/Ti photoanode with polydopamine as electron transfer mediator for efficient visible-light driven photocatalytic fuel cell

Abstract In order to enhance the electron transmission rate of photocatalytic fuel cell (PFC), BiVO4@PDA-wt% composite was successfully prepared by hydrothermal synthesis and chemical polymerization method, and used to modify TiO2/Ti to obtain BiVO4@PDA/TiO2/Ti photoanode with high efficient visible light-response. The structure, morphology, optical and photoelectrochemical properties of BiVO4@PDA/TiO2/Ti photoanode were characterized and explored. BiVO4@PDA-10 %/TiO2/Ti obtained the maximum photocurrent density of 10.68 mA cm−2 at 1.0 V (vs. SCE) under visible light illumination, which was 4.7 times that of BiVO4/TiO2/Ti. This is because of its extended π-conjugated electron system, PDA can significantly promote the charge transfer between BiVO4 and TiO2. Therefore, the separation of photogenerated electrons and holes in space can be realized, thereby the recombination of photogenerated electron-hole pairs can be reduced and ultimately the photocatalytic performance can be enhanced. With BiVO4@PDA-10 %/TiO2/Ti photoanode and Cu2O/Cu cathode, the visible-light responsive PFC exhibited high organics degradation and electricity conversion performance. Its photocurrent density, maximum power density and Rhodamine B degradation efficiency were 0.42 mA cm−2, 58.55μW cm−2 and 97.28 %, respectively.