Abstract
Separation of photogenerated electrons from holes is an important factor that increases hydrogen evolution rate in the water splitting reaction. This recombination prevention can be achieved by co-catalyst's deposition onto the semiconductor material's surfaces. In this contribution, synthesis of mesoporous C3N4 of graphite-like structure by a combustion technique employing high mesoporous silica as a template has been achieved. Subsequently, NiS nanoparticles were decorated as g-C3N4 nanosheets at various NiS contents (5-20%). the photocatalytic efficiency of the prepared NiS/g-C3N4 nanocomposites was investigated and compared with those of pure NiS and g-C3N4 for evolution of hydrogen using glycerol as a scavenger upon visible light illumination. The findings indicated that the content of deposited NiS nanoparticles onto g-C3N4 is significant in the enhancement of the photocatalytic response of g-C3N4. 15% NiS/g-C3N4 nanocomposite is the optimized photocatalyst and its photocatalytic activity is larger than both NiS and g-C3N4 by about 48 and 114 times, respectively. 15% NiS/g-C3N4 nanocomposite has photocatalytic stability up to five times. The enrichment of the photocatalytic efficiency of NiS/g-C3N4 photocatalyst could be attributed to the presence of NiS nanoparticles as co-catalyst, which enables efficient charge carrier separation of g-C3N4, mesostructure, large surface area and narrow band gap.