Ultra-thin SiC layer covered graphene nanosheets as advanced photocatalysts for hydrogen evolution

Abstract

Herein, for the first time, ultra-thin SiC nanoparticles or ultra-thin layer covered graphene nanosheets were successfully prepared via using a facile in situ vapor–solid reaction. The samples were characterized by X-ray diffraction, UV-visible spectroscopy, photoluminescence spectra analysis, Raman spectra, transient photocurrent responses and transmission electron microscopy. The photocatalytic activities were also evaluated by H₂ evolution from pure water or water containing Na₂S as an electron donor. The resulting SiC–graphene hybrids show enhanced photocatalytic H₂-evolution activities in the presence of an electron donor. Especially, the graphene nanosheet and SiC nanocrystal hybrids show the highest photocatalytic activity in H₂ production under visible light, which is about 10 times higher than that of the SiC nanocrystals. The enhanced activities of the SiC–graphene hybrids can be attributed to their 2D nanosheet structures, large surface area, enhanced visible-light absorption and rapid interfacial charge transfer from SiC to graphene. Our results can provide an effective approach to synthesize graphene-based heterogeneous nanocomposites for a wide variety of potential applications in solar energy conversion and storage, separation, and purification processes.