Progress on enhancing the charge separation efficiency of carbon nitride for robust photocatalytic H₂ production

Solar-driven H₂ production from water splitting with efficient photocatalysts is a sustainable strategy to meet the clean energy demand and alleviate the approaching environmental issues caused by fossil fuel consumption. Among various semiconductor-based photocatalysts, graphitic carbon nitride (g-C₃N₄) has attracted much attention due to its advantages of long term-stability, visible light response, low cost, and easy preparation. However, the intrinsic Coulombic attraction between charge carriers and the interlayer electrostatic barrier of bulk g-C₃N₄ result in severe charge recombination and low charge separation efficiency. This perspective summarizes the recent progress in the development of g-C₃N₄ photocatalytic systems, and focuses on three main modification strategies for promoting charge transfer and minimizing charge recombination, including structural modulation, heterojunction construction, and cocatalyst loading. Based on this progress, we provide conclusions regarding the current challenges of further improving photocatalytic efficiency to fulfill commercial requirements, and propose some recommendations for the design of novel and satisfactory g-C₃N₄ photocatalysts, which is expected to progress the solar-to-hydrogen conversion.