The BS Nanotubes with High Carrier Mobility for Potential Photocatalytic Hydrolysis Applications: First-Principles Study

To explore the photocatalytic properties of BS, we have investigated the geometry, electronic structure, and carrier mobility of BS monolayer and single-walled nanotubes (SWNTs) using a first-principles study. The B-S and B-B bond lengths of SWNTs remain stable compared to the monolayer, and the strain energy and formation energy decrease with the increase of the diameter of the nanotube. The band gap of nanotubes is significantly reduced compared to that of the monolayer, and the transition from indirect to direct band gap occurs between monolayer to nanotubes which promotes rapid carrier migration while reducing electron-hole recombination. The band gap edge position of larger diameter BS nanotubes satisfies the photocatalytic hydrolysis redox potential. Notably, the electron mobility of the (60, 0) nanotube is 97.22 cm² V⁻¹ s⁻¹ while the hole mobility of the nanotube is as high as 4684.61 cm² V⁻¹ s⁻¹. The large value difference in carrier mobility could reduce the recombination of electrons and holes. Combined with the above calculations, we believe that the BS nanotubes have good photocatalytic performance and these BS nanotubes in photocatalytic hydrolysis should be very promising.