Flower-Like Dual-Defective Z-Scheme Heterojunction g-C3N4/ZnIn2S4 High-Efficiency Photocatalytic Hydrogen Evolution and Degradation of Mixed Pollutants

Graphitic carbon nitride (g-C3N4) with a porous nano-structure, nitrogen vacancies, and oxygen-doping was prepared by the calcination method. Then, it was combined with ZnIn2S4 nanosheets containing zinc vacancies to construct a three-dimensional (3D) flower-like Z-scheme heterojunction (pCN-N/ZIS-Z), which was used for photocatalytic hydrogen evolution and the degradation of mixed pollutants. The constructed Z-scheme heterojunction improved the efficiency of photogenerated charges separation and migration, and the large surface area and porous characteristics provided more active sites. Doping and defect engineering can change the bandgap structure to improve the utilization of visible light, and can also capture photogenerated electrons to inhibit recombination, so as to promote the use of photogenerated electron-hole pairs in the photocatalytic redox process. Heterojunction and defect engineering synergized to form a continuous and efficient conductive operation framework, which achieves the hydrogen production of pCN-N/ZIS-Z (9189.8 mu mol center dot h(-1)center dot g(-1)) at 58.9 times that of g-C3N4 (155.9 mu mol center dot h(-1)center dot g(-1)), and the degradation rates of methyl orange and metronidazole in the mixed solution were 98.7% and 92.5%, respectively. Our research provides potential ideas for constructing a green and environmentally friendly Z-scheme heterojunction catalyst based on defect engineering to address the energy crisis and environmental restoration.

Automated summary

The research involved the preparation of g-C3N4 with specific structural features and combination with ZnIn2S4 nanosheets to create a Z-scheme heterojunction with enhanced photocatalytic properties. The synergistic effect of heterojunction and defect engineering led to significantly improved hydrogen production and degradation rates of mixed pollutants. The study provides potential ideas for constructing green and environmentally friendly catalysts based on defect engineering to address energy and environmental challenges.