Enhanced photoelectrochemical performance of CdSe quantum dot sensitized SrTiO3

Abstract

We report the design and characteristics of a novel CdSe quantum dot sensitized SrTiO₃ as a photoanode for photoelectrochemical water splitting with strong absorption in the UV and visible light regions up to 607 nm and an enhanced photocatalytic water splitting activity. Our results demonstrate an increase of photocurrent density with a decrease of the band gap of CdSe QDs for the sensitized SrTiO₃ electrodes. Combinations of CdSe QDs of different band gaps produce a current density of up to ∼5 mA cm⁻² at 0 V and ∼18 mA cm⁻² at 0.75 V vs. Ag/AgCl. In comparison to the bare SrTiO₃ electrode, a two-time increase in the current density is noted for the CdSe QD sensitized SrTiO₃ electrodes at 0.75 V vs. Ag/AgCl. Our results demonstrate for the first time the use of SrTiO₃ perovskite sensitized with tuned band gap CdSe QD heterostructures as a photoelectrocatalyst for enhanced solar water splitting.