NH-MIL-125/g-CN/BiO/Ti photoanode for visible light responsive photocatalytic fuel cell degradation of rhodamine B and electricity generation

The low electron-hole separation in the photoanode generally restricts the visible light response of photocatalytic fuel cell (PFCs). In this study, 5% NH 2 -MIL-125/g-C 3 N 4 /Bi 2 O 3 /Ti photoanode was synthesized and assembled with a PFC with Cu cathode to degrade rhodamine B and generate electricity. With visible light irritation, the maximum photocurrent density, maximum power density, and degradation rate of the PFC were 0.59 mA cm −2 , 29.88 μW cm −2 , and 97.48% (1 h), respectively. The major active species in the PFC were h + , &z.rad;O 2 − , and &z.rad;OH. The good performance of the PFC was ascribed to the formation of a double Z-type heterojunction in the 5% NH 2 -MIL-125/g-C 3 N 4 /Bi 2 O 3 /Ti photoanode so that the photoelectrons of NH 2 -MIL-125 and Bi 2 O 3 directly combine with the photoholes of g-C 3 N 4 , making the photoholes of NH 2 -MIL-125 and Bi 2 O 3 and the photoelectrons of g-C 3 N 4 directly or indirectly involved in the RhB degradation process and generating electricity. Thus, the separation rate of the e − -h + pairs in the photoanode and the capability of the PFC are greatly improved. The synergy effect realizes the rapid separation of photogenerated carrers and ultimately improves the photoelectric conversion efficiency of PFC.