Carbon Coated TiO 2 Photoanodes for All-vanadium Redox Photoelectrochemical Cells as Efficient Solar Energy Storage Device

Abstract

An all-vanadium redox photoelectrochemical cell with a carbon coated TiO 2 photoelectrode was designed to convert/store solar energy as a promising alternative to photogeneration of hydrogen. In this study, a facile high-temperature sintering approach was employed to tailor the thickness of the carbon coating at TiO 2 photoanodes. Considerable enhancement in photocurrent has been observed using the carbon coated TiO 2 photoanode in the all vanadium photoelectrochemical system when compared to the carbon-free counterpart. Particularly, the photoanode containing 2.07 wt% of carbon displayed 40% improvement in photocurrent compared to the one with bare TiO 2 as the photoanode. It is proposed that the carbonaceous species created by high-temperature pyrolysis acted as a thin adsorption layer on the TiO 2 for VO 2+ to react with the photogenerated holes. Photocurrent enhancement of the carbon coated photoelectrodes is ascribed to a synergic effect between enhanced charge separation and high conductivity.