In direct photoelectrochemical reduction of CO2, ptype semiconductors are usually used as photocathode to supply light-induced electrons to reduce CO2. However, since the band position at the surface of semiconductor is fixed, the overpotential of CO2 reduction reaction at the interface is unchangeable. Therefore, it is impossible to boost the interfacial reaction through increasing interfacial overpotential. A photoelectrochemical cell (PEC) that consists of an ntype photoanode and a metal cathode offers the opportunity to manipulate the cathode overpotential. Furthermore, by applying different pH values for the anolyte and catholyte, the PEC can be self-contained and no bias voltage is needed.
Keywords photoelectrochemical, photoanode, carbon dioxide reduction