Benthic microbial fuel cell equipped with a photocatalytic Cu2O-coated cathode

In this study, a photocatalytic benthic microbial fuel cell was developed and the cell performance was tested. A photocathode was fabricated by electrodeposition of Cu2O photocatalysts on carbon felt; with a proper deposition time of 15 min, a photocathode with optimal Cu2O compactness and an average Cu2O particle size of 0.97 μm was fabricated and was then covered with an amorphous carbon thin layer. Photoelectrochemical test results prove the pronounced visible light response of the fabricated photocathode. Results show that the coating of carbon thin layer could protect the Cu2O from self-reduction and also improve the photoelectrochemical performance of Cu2O crystalline grains. The photo-benthic microbial fuel cell (BMFC) produces a maximum power density of 249.0 mW m−2 and 186.7 mW m−2 under light irradiation and in the dark, which is 17.8 and 13.3 times higher than the common BMFC using carbon felt cathode in parallel, demonstrating the catalytic and photocatalytic effect of the fabricated photocathode. Polarization and EIS results prove the decrease of internal resistance by using the photocathode. The fabricated photocathode could improve the oxygen reduction rate on the cathode side, thus reduce the internal resistance and enhance the BMFC performance.