A facile hydrothermal synthesis of carbon dots modified g-C₃N₄ for enhanced photocatalytic H₂-evolution performance

Carbon dots (CDs)/g-C₃N₄ is a promising photocatalyst to split water for H₂ production; however, the synthesis of CDs/g-C₃N₄ is usually rigorous and involves multiple steps, which limits its practical application. In this study, a facile hydrothermal approach was developed to prepare CDs/g-C₃N₄ photocatalysts using l-ascorbic acid and g-C₃N₄ as the precursors. Upon in situ thermal polymerization of l-ascorbic acid on the g-C₃N₄ surface, the carbon dots were homogeneously and solidly modified on the g-C₃N₄ surface. The CDs/g-C₃N₄ photocatalysts showed higher photocatalytic performance for H₂ production than g-C₃N₄ under UV light irradiation using lactic acid as the sacrificial agent. The improved photocatalytic performance of CDs/g-C₃N₄ was mainly attributed to rapid interfacial charge transfer. After a Pt co-catalyst was loaded, the Pt-CDs/g-C₃N₄ catalyst formed exhibited a further improved photocatalytic performance for H₂ production and could even split pure water to produce H₂. Considering our present economic and facile synthetic approach for the modification of carbon dots on the surface of g-C₃N₄ photocatalysts, the as-prepared CDs/g-C₃N₄ photocatalysts will be promising for practical use in water splitting.