CdS quantum dots sensitized platelike WO3 photoelectrodes with a TiO2 buffer-layer

• A facile route to prepare CdS QDS sensitized platelike WO3 photoelectrodes with a TiO2 buffer-layer.
• CdS QDs/TiO2/WO3 photoelectrodes can stably operate the water splitting process in an alkaline environment.
• CdS QDs/TiO2/WO3 electrodes show excellent photoelectric property.

High chemical stability of WO3 photoelectrode sensitized with CdS quantum dots (QDs) was reported for the first time using nano-TiO2 as a buffer layer, permitting their stable operation for photoelectrochemical water splitting in a strongly alkaline electrolyte solution. The CdS QDs modification of the TiO2/WO3 electrode resulted in an increase in the visible light absorption and exhibited a significant improvement in photoelectrochemical performance. The photocurrent density at −0.1 V (vs. Ag/AgCl) of the CdS QDs/TiO2/WO3 electrode is 10 times higher than that of the TiO2/WO3 electrode under visible light irradiation. The demonstrated strategies of utilizing a TiO2/WO3 structure to protect the WO3 electrode surface open up new opportunities for other WO3 nanostructures.