Photocatalytic reforming of biomass for hydrogen production over ZnS nanoparticles modified carbon nitride nanosheets

Abstract

Hydrogen generation from biomass reforming via solar energy utilisation has become a fascinating strategy toward future energy sustainability. In this study, ZnS nanoparticles with an average size around 10-15 nm were synthesised by a facile hydrothermal method, and then hybridised with g-C3N4 (MCN, DCN, and UCN) derived from melamine, dicyandiamide and urea, producing the heterojunctions denoted as ZMCN, ZDCN and ZUCN, respectively. Advanced characterisations were employed to investigate the physiochemical properties of the materials. ZMCN and ZDCN showed a slight red shift and better light absorbance ability. Their catalytic performances were evaluated by photocatalytic biomass reforming for hydrogen generation. The hydrogen generation rate on ZMCN, the best photocatalyst among MCN, DCN, UCN, ZDCN and ZUCN, was around 2.5 times higher than the pristine MCN. However, the photocatalytic efficiency of ZUCN experienced decrease of 36.6% compared to pure UCN. The mechanism of the photocatalytic reforming process was discussed. The photoluminescence spectra of ZMCN suggested that the introduction of ZnS for ZMCN would reduce the recombination of photoinduced carriers. It was also found that both microstructure and band structure would influence the photocatalytic reforming efficiency.