Synthesis of metal sulfide/g-C₃N₄ nanocomposite for photocatalytic degradation of organic pollutants under visible light

Graphitic carbon nitride (g-C₃N₄) is an intriguing two-dimensional (2D) material characterized by remarkable features, such as visible light absorption, superior thermal stability, and a large abundance of its components in the Earth's crust. In contrast to conventional photocatalysts like titanium dioxide (TiO₂), g-C₃N₄ may function well in visible light, which constitutes a substantial segment of the solar spectrum. This makes it a more sustainable alternative for environmental cleanup. Nonetheless, the efficacy of pure g-C₃N₄ in photocatalysis is impeded by challenges such as the rapid recombination of electron–hole pairs and a very limited surface area. To tackle these issues, g-C₃N₄ is modified with metal sulfides such as zinc sulfide (ZnS) and bismuth sulfide (Bi₂S₃) by a simple, sustainable process employing starch. These adjustments boost charge carrier separation and improve light absorption, leading to a significant increase in photocatalytic efficiency.
These composite materials have shown remarkable efficacy in effectively degrading coumarin and para-nitrophenol upon exposure to visible light. The amalgamation of g-C₃N₄ and metal sulfides markedly enhances degradation rates, making them very useful for environmental remediation applications. This advancement offers an effective and eco-friendly method for degrading organic contaminants present in wastewater and industrial discharges.

This work was supported by the National Research, Development, and Innovation Office of Hungary in the frame of the bilateral Hungarian-Vietnamese S&T Cooperation Program (project code 2019-2.1.12-TÉT_VN-2020-00009) and by the Ministry for Innovation and Technology of Hungary from the National Research, Development and Innovation Fund, financed under the 2021 Thematic Excellence Program funding scheme (grant number TKP2021-NKTA-21).