Hydrogen and electricity production in a light-assisted microbial photoelectrochemical cell with CaFe₂O₄ photocathode

A microbial photoelectrochemical cell (MPEC) was designed with a p-type CaFe₂O₄ semiconductor as the photoelectrode for simultaneous hydrogen and electricity production under light illumination. The CaFe₂O₄ photoelectrode was synthesized by the sol-gel method and well characterized by x-ray diffraction, field emission scanning electron microscope, and UV-Vis-NIR spectrophotometer. The linear sweep voltammogram of the CaFe₂O₄ photoelectrode presented the cathodic photocurrent output. For the MPEC, with an external resistance of 2000 Ω, the maximum power density of 143 mW·m^-2 was obtained. Furthermore, with an external resistance of 100 Ω, the maximum hydrogen production rate of 6.7μL·h-1·cm^-2 could be achieved. The MPEC with CaFe₂O₄ photocathode was compared to MPEC with other photocathodes as well as photocatalytic water splitting technology.