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

Metal-free semiconductors with desirable characteristics have recently gained great attentions in the field of hydrogen generation. The non-metal material B2S3comprise 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 band gaps of 2.89 and 3.77 eV by HSE functional, respectively. Under proper uniaxial strains (1%), the band gap ofh-B2S3can be decreased to 2.8 eV. The carrier mobility can reach 1160 cm2V-1s-1, illustrating a fast migration of photo-induced carriers. Most importantly, the band edges of bothh-B2S3ando-B2S3can properly cover the reduction and oxidation levels for water splitting. Then we explore the process of photocatalytic water splitting onh-B2S3monolayers by analyzing the feasibility of the decomposition of H2O and the generation of H2. It indicates that the special mesoporous structure of B2S3is helpful for photocatalytic hydrogen production. The new nanomaterial B2S3offers great promise as metal-free photocatalysts thanks to the tunable band gaps, proper band edges and other excellent electronic properties.