Synthesis and Characterization of Boron-Doped SiC for Visible Light Driven Hydrogen Production

Boron-doped beta-SiC (BxSiC) photocatalysts were prepared by in-situ carbothermal reduction, and their photocatalytic performances for H-2 evolution under visible light irradiation were investigated. The crystal structure, surface property, morphology, and band gap structure of the BxSiC photocatalysts were studied using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and ultraviolet-visible absorption spectroscopy. The characterization results indicate that B atoms have doped into the SiC lattice and substituted Si sites, leading to the formation of a shallow acceptor level above the valence band of SiC, resulting in a narrowed band gap energy. The shallow acceptor level acts as a hole trap, preventing the recombination of photo-excited electrons and holes. Therefore, the photocatalytic H-2 evolution activity of B-doped SiC was greatly improved compared with that of SiC. The highest hydrogen evolution rate was obtained when the B/Si molar ratio was 0.05.