The co-decorated TiO2 nanorod array photoanodes by CdS/CdSe to promote photoelectrochemical water splitting

A cascade structure of TiO2/CdS/CdSe semiconductor heterojunction is synthesized using a three-step technique of facile hydrothermal growth for the enhancement of the photo-electrochemical performances. The optical and photoelectrochemical properties controlled by the deposition processing parameters have been investigated. It is shown that the pat-terns of semiconductor heterojunction enlarge the absorption range of solar spectra, and improve the properties of the photogenerated charge carriers describing separation and transportation, and reduce the interface resistance between the photoelectrode and elec-trolyte comparing with the pure TiO2 and CdS-decorated TiO2 nanorod array photoanodes. The higher photocurrent density and photoconversion efficiency are up to 4.23 mA cm-2 and 4.2%, which are the 4.1 and 25.3 times superior than that of the pure TiO2 photoanode. The hydrothermal growth time increment of CdSe yields greater photoelectrochemical water splitting performances. The underlying physics mechanisms have been discussed based on forming a type-II energy band alignment structure. (c) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

The cascade structure of TiO2/CdS/CdSe semiconductor heterojunction, synthesized by a three-step hydrothermal growth technique, enhances photo-electrochemical performances by enlarging the absorption range of solar spectra, improving the properties of photogenerated charge carriers, and reducing interface resistance. The increase in hydrothermal growth time of CdSe leads to greater photoelectrochemical water splitting performances. The underlying physics mechanisms are discussed based on the formation of a type-II energy band alignment structure.