CuInS2 quantum-dot-modified g-C3N4 S-scheme heterojunction photocatalyst for hydrogen production and tetracycline degradation

CuInS2 quantum-dot (CIS QD)-modified g-C3N4 (CN) catalysts (CIS/CN) were prepared with the aid of an in-situ growth process. The as-obtained photocatalysts were explored by measuring their crystallinity, surface morphology, binding energy and light absorption activity. The photocatalytic efficiency of the photocatalysts was evaluated through photocatalytic water splitting for hydrogen production and tetracycline (TC) antibiotic degradation under the simulated solar light and visible light respectively. The optimized sample (10CIS/CN) showed the best photocatalytic activity: producing 102.4 µmol g−1 h−1 of hydrogen in 1 h, or degrading 52.16% of TC in 120 min, which were respectively 48 or 3.4 times higher than the photocatalytic activity of CN itself. The enhancement in the efficiency of the composite system was principally accredited to the enlargement of light absorption, the more effective in charge transfer and the dropping of the charge carrier pair recombination through a formed S-scheme heterojunctional interface. This work is an effort to adjust CN-based polysulfide QD for speedy photocatalysis. The enriched photocatalytic activity grants a new sense for adjusting the optical properties of CN.