P-Type Cu-Doped Zn0.3Cd0.7S/Graphene Photocathode for Efficient Water Splitting in a Photoelectrochemical Tandem Cell

By doping Cu(I) ions in Zn0.3Cd0.7S, a novel p-type Cu doped Zn0.3Cd0.7S modified graphene (Zn0.3Cd0.7S (Cu)/GR) film photocathode was prepared. The as-prepared p-type Zn0.3Cd0.7S (Cu)/GR photocathode and an n-type WO3/graphene (WO3/GR) photoanode were used to assemble a photoelectrochemical tandem cell. Through examination of the optoelectronic and photoelectrochemical properties of Zn0.3Cd0.7S (Cu)/GR and WO3/GR photoelectrode, we evaluate the feasibility of the tandem cell for overall water splitting under UV-vis light irradiation. The optimal Cu doping in Zn0.3Cd0.7S photocathode concentration was found to be 6%. The rates of hydrogen and oxygen evolved from this tandem cell with the optimal electrodes were 65.6 and 12.3 mu mol g(-1) h(-1) (80.5 and 15.1 mu mol cm(-2) h(-1)), respectively. This study suggests a promising method for constructing an efficient photoelectrochemical tandem device for overall water splitting.