Application of microbial fuel cells with tungsten-based semiconductor modified electrode in the treatment of Cr (VI) pollutions

The cathodic reduction of Cr (VI) accompanied by power generation is effectively carried out in a photocatalytic microbial fuel cell (PMFC) utilizing a WO3/CF anode in conjunction with a hybrid photocathode consisting of Fe3O4, FeWO4, and CP. This process occurs under both light illumination and dark conditions. The experimental results indicate that the biocompatibility and enhanced conductivity of WO3 promote improved adhesion and charge transfer between bacteria and the electrode material. Compared to CF/MFC (with an operating voltage of 0.202 V, power density of 56.67 mW/m2, and Coulomb efficiency of 7.47%), the MFC with a 5 mg/cm2 WO3/CF anode demonstrates improved performance in terms of operating voltage (0.288 V), power density (124.29 mW/ m2), and Coulomb efficiency (11.4%). Furthermore, the heterojunction formed between Fe3O4 and FeWO4 increases the concentration of charge carriers and reduces electron-hole recombination during the photocatalysis process. When exposed to 200 W LED illumination, the PMFC with a 20% Fe3O4/FeWO4/CP hybrid achieves a remarkable 99.98% reduction rate of Cr (VI) within 28 h, while the unmodified cathode requires an additional 30 h. These findings emphasize the promising potential of tungsten-based semiconductors in PMFCs, owing to their facile and scalable synthetic approach, as well as their stable and exceptional photoelectrocatalytic performance.