Theoretical study on the photocatalytic potential of BSe nanotubes for water splitting under visible light

Photocatalytic splitting of water has been a useful tool in recent years for solving the world's energy and environmental problems. However, the wide band gap and low carrier mobility of traditional photocatalysts are the reasons that limit their wide application. In this work, the structure, and optical properties of BSe nanotubes are studied for the first time based on density functional theory. The results show that single-walled BSe nanotubes (SW BSe NTs) not only have a stable structure but can also extend the ultraviolet light absorption range of the BSe monolayer to the visible light range. Significantly, the SW BSe NT has excellent photoreduction ability, low electron-hole recombination rate, and high hole carrier mobility (similar to 10(3) cm(2)V(-1)s(-1)). Under uniaxial strain, the SW BSe NT exhibits a direct-indirect band gap transition. Furthermore, the electronic structure double-walled BSe nanotubes facilitates charge separation and has a wider range of light absorption. Unluckily, its lower band edge position prevents it from having an overall photocatalytic decomposition capability. Our results show that SW BSe NTs have potential applications in visible light-driven photocatalytic water splitting.