Novel 2D B2S3 as a metal-free photocatalyst for water splitting

摘要

Metal-free semiconductors with desirable characteristics have recently gained great attention in the field of hydrogen generation. The non-metal material B2S3 has two phases, hexagonal B2S3 (h-B2S3) and orthorhombic B2S3 (o-B2S3), which compose a novel class of 2D materials. Both h-B2S3 and o-B2S3 monolayers 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 of h-B2S3 can be decreased to 2.8 eV. The carrier mobility can reach 1160 cm(2) V-1 s(-1), supporting the fast migration of photo-induced carriers. Most importantly, the band edges of both h-B2S3 and o-B2S3 cover the reduction and oxidation levels for water splitting. We explore the process of photocatalytic water splitting on h-B2S3 monolayers by analyzing the feasibility of the decomposition of H2O and the generation of H-2. The results indicate that the special mesoporous structure of B2S3 is 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.