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

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 Xray diffraction, UV-visible spectroscopy, photoluminescence spectra analysis, Raman spectra, transient photocurrent responses and transmission electron microscopy. The photocatalytic activities were also evaluated by H-2 evolution from pure water or water containing Na2S as an electron donor. The resulting SiC-graphene hybrids show enhanced photocatalytic H-2-evolution activities in the presence of an electron donor. Especially, the graphene nanosheet and SiC nanocrystal hybrids show the highest photocatalytic activity in H-2 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.