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

In order to enhance the electron transmission rate of photocatalytic fuel cell (PFC), BiVO 4 @PDA-wt% composite was successfully prepared by hydrothermal synthesis and chemical polymerization method, and used to modify TiO 2 /Ti to obtain BiVO 4 @PDA/TiO 2 /Ti photoanode with high efficient visible light-response. The structure, morphology, optical and photoelectrochemical properties of BiVO 4 @PDA/TiO 2 /Ti photoanode were characterized and explored. BiVO 4 @PDA-10 %/TiO 2 /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 BiVO 4 /TiO 2 /Ti. This is because of its extended π-conjugated electron system, PDA can significantly promote the charge transfer between BiVO 4 and TiO 2. 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 BiVO 4 @PDA-10 %/TiO 2 /Ti photoanode and Cu 2 O/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.