A solar-driven photocatalytic fuel cell with dual photoelectrode for simultaneous wastewater treatment and hydrogen production

Abstract

A solar-driven dual photoelectrode photocatalytic fuel cell (PFC) based on n-type semiconductor photoanode and p-type semiconductor photocathode is reported for wastewater treatment with simultaneous hydrogen production. The PFC shows a superior performance for phenol degradation and hydrogen production with a maximum TOC removal rate of 84.2% and a total hydrogen production rate of 86.8 μmol cm⁻² in 8 hours which is much higher than other similar researches. Compared to the system comprised of a photoanode (photocathode) and Pt for phenol degradation (hydrogen production), the results prove that there is a synergistic effect between the two photoelectrodes. This is because the electrons are preferentially stored on the photocathode for hydrogen production and holes on the photoanode for pollutant degradation. Several semiconductors are chosen as photoelectrodes to investigate the factors influencing the performance of the PFC system. The V_OC value of the PFC increases with the difference of Fermi level between the two photoelectrodes. This PFC system provides a new approach for efficient energy recovery from wastewater.