Efficiency enhancement in a stoichiometrically stable CdS/TiO2 nanotube heterostructure electrode for sunlight-driven hydrogen generation

A stoichiometrically stable CdS/TiO2 heterostructured electrode was developed via electrodeposition for efficient photoelectrochemical conversion. The stoichiometry of CdS and its homogeneous distribution over TiO2 nanotubes (TNTs) is paramount to achieve excellent current conversion efficiency and photo-stability. Herein, we report a stable photocurrent density of 3.5 mA cm(-2) for an input power density of 50 mW cm(-2) for CdS/TiO2 nanotubes (CdS/TNTs), which is 17 times higher than that of bare TNTs. Further, the photo-stability of the photoanode was studied under the sequence of light ON/OFF conditions to verify their durability. Our results show that the photoelectrochemical activity of the CdS/TiO2 heterostructure achieved the highest H-2 production rate of 1.1 +/- 0.03 mmol h(-1) g(-1) for the stoichiometry ratio of 1 : 1 without any co-catalysts. The significance of CdS/TiO2 stoichiometry towards efficient hydrogen production is presented and discussed in detail.

Automated summary

A stoichiometrically stable CdS/TiO2 heterostructured electrode was developed for efficient photoelectrochemical conversion, with CdS evenly distributed over TiO2 nanotubes. The electrode exhibited a stable photocurrent density of 3.5 mA cm(-2) and achieved a high H-2 production rate of 1.1 ± 0.03 mmol h(-1) g(-1) without any co-catalysts. The significance of CdS/TiO2 stoichiometry towards efficient hydrogen production was discussed in detail.