Enhanced solar absorption and photoelectrochemical properties of Al-reduced TiO2/TiO2−x/CdS heterojunction nanorods

Abstract

Oxygen-deficient TiO₂-based composites have attracted widespread attention due to their promoted light-harvesting capacity and energy conversion efficiency, beneficial for water splitting. Despite being a facile, secure-safe and undefiled route for preparing blackened TiO₂, the Al-reduction method has not been adopted for preparing TiO₂/TiO_2−x/CdS composite films. Herein, TiO₂/TiO_2−x/CdS composite nanorods were successfully fabricated by combining hydrothermal, Al-reduction and chemical bath deposition (CBD) techniques. Enhanced visible-light absorption and photoelectrochemical performances have been achieved using TiO₂/TiO_2−x/CdS heterojunction nanorods. The photocurrent density of TiO₂/TiO_2−x/CdS was obtained to be 7.75 mA cm⁻² at 0 V vs. Ag/AgCl under AM 1.5 G illumination, which was 77.5-fold and 12.1-fold higher than those of bare TiO₂ and CdS, respectively. This work may offer new insights for realizing TiO₂-based composites with improved solar absorption for photoelectrochemical applications.