Effect of light irradiation on the photoelectricity performance of microbial fuel cell with a copper oxide nanowire photocathode

• CuO nanowire was used as the cathode in photoelectrochemical microbial fuel cell.
• The output and open circuit voltages of the cell increased under light irradiation.
• Preliminary mechanism of the photoelectrochemical microbial fuel cell was elucidated.

A new way to enhance the performance of a microbial fuel cell (MFC) using photoelectricity was studied. The effect of light irradiation on the photoelectricity performance of a MFC with CuO nanowire-arrayed photocathode was investigated. The MFC produced a maximum power density of 46.44 mW m−2 under light irradiation, 125% increase compared to 36.99 mW m−2 in the dark. The open circuit voltage (Vocv) of the MFC was 466 mV under light irradiation, which increased by 113% compared to 412 mV in the dark. The linear sweep voltammogram (LSV) of the MFC cathode proved that the CuO cathode current was higher under light illumination than in the dark. The electrochemical impedance spectrum of the CuO cathode was lower under light irradiation conditions than in the dark. The results show that the Rct and RΩ of the CuO cathode under light irradiation decreased from 179.9 and 7.92 Ω to 138.6 and 2.04 Ω, respectively. The resistance of the photoelectrode decreased and the cathode potential increased, thus increasing the MFC power. The cathodes made of semiconductor materials such as copper oxide nanowires were used for the first time in MFC, which cooperated with the solar and biomass energy in MFC. The study provided a new insight into the biological energy coupling with solar energy and provided exciting opportunities for the unique study in semiconductor and MFC.