Novel 2D B₂S₃as a metal-free photocatalyst for water splitting

Metal-free semiconductors with desirable characteristics have recently gained great attention in the field of hydrogen generation. The non-metal material B₂S₃has two phases, hexagonal B₂S₃(h-B₂S₃) and orthorhombic B₂S₃(o-B₂S₃), which compose a novel class of 2D materials. Bothh-B₂S₃ando-B₂S₃monolayers are direct semiconductors with bandgaps of 2.89 and 3.77 eV by the Heyd-Scuserria-Ernzerhof (HSE) function, respectively. Under appropriate uniaxial strain (1%), the bandgap ofh-B₂S₃can be decreased to 2.8 eV. The carrier mobility can reach 1160 cm²V^-1s^-1, supporting the fast migration of photo-induced carriers. Most importantly, the band edges of bothh-B₂S₃ando-B₂S₃cover the reduction and oxidation levels for water splitting. We explore the process of photocatalytic water splitting onh-B₂S₃monolayers by analyzing the feasibility of the decomposition of H₂O and the generation of H₂. The results indicate that the special mesoporous structure of B₂S₃is helpful for photocatalytic hydrogen production. The new nanomaterial, B₂S₃, offers great promise as a metal-free photocatalyst due to its tunable bandgaps, its useful band edges, and its other excellent electronic properties.