Bismuth doped TiO2 as an excellent photocathode catalyst to enhance the performance of microbial fuel cell

Abstract Bismuth impregnation on pure TiO 2 (Bi TiO 2 ) was carried out and tested in microbial fuel cell (MFC) as photocathode catalyst. UV–Visible spectral observation confirmed higher catalytic activity of Bi TiO 2 under visible light irradiation with reduced band gap of 2.80 eV as compared to pure TiO 2 (3.26 eV). Electrochemical impedance spectroscopy also showed two times higher exchange current density with lower charge transfer resistance for Bi TiO 2 (1.90 Ω) than pure TiO 2 (3.95 Ω), thus confirming it as superior oxygen reduction reaction catalyst. MFC operated with Bi TiO 2 could generate a maximum power density of 224 mW m −2 , which was higher than MFC with Pt as cathode catalyst (194 mW m −2 ) and much higher than MFCs with TiO 2 catalyzed cathode (68 mW m −2 ) and without any cathode catalyst (60 mW m −2 ). The results thus promote Bi doped TiO 2 as a superior low-cost alternative to the costly Pt catalyst to take this MFC technology forward for field application.