Photoenhanced interfacial electron transfer of a dual functional hematite biophotoelectrode

Abstract

A promising method to boost the effectiveness of bioelectrochemical systems is to combine the light-harvesting properties of semiconductors with the catalytic strength of bacteria. Here, we demonstrate the improved photocurrents generated by the interaction of Shewanella oneidensis MR-1 and a hematite nanowire-arrayed photoanode in a solar-assisted microbial photoelectrochemical cell (S-MPEC) under visible light. The S-MPEC uses the technology of bioelectrochemical cells and photoelectrochemical cells (PECs) for enhancing the degradation of pollutants from wastewater treatment under irradiation. The bare Fe₂O₃ photoelectrode exhibits a photocurrent of 1.093 A m⁻² at 0.8 V under visible light, whereas the Fe₂O₃-MR-1 biophotoelectrode exhibits a higher photocurrent of 1.605 A m⁻². With visible light exposure at an intensity of less than 100 mW cm⁻², the power densities of the Fe₂O₃ photoelectrode system with and without coating the MR-1 bacteria are 1.284 W m⁻² and 0.872 W m⁻², respectively. Besides, based on the study of the heterogeneous electron transfer kinetics, the reduction and oxidation reactions of Fe₂O₃-MR-1 exhibit more efficient diffusion coefficients with enhanced rate constants. These findings demonstrate a significant impact on degradation performance induced by photoexcited charge carriers in a complicated hybrid electricigen system, which is critical for the development of a S-MPEC for waste degradation.