Graphitic Carbon Nitride-Based Low-Dimensional Heterostructures for Photocatalytic Applications

Low-dimensional materials and heterostructure photocatalysts are distinct research topics in artificial photocatalysis. The rational design of photocatalysts considering both aspects has established significant importance due to the fascinating advantages of superior charge carrier transport/transfer and photocatalytic performances. Graphitic carbon nitride (g-C₃N₄), a captivating metal-free and visible light-active photocatalyst, has drawn interdisciplinary attention in the field of solar energy conversion and pollutant degradation because of its appropriate electronic band structure, excellent physicochemical stability, facile synthesis, and unique layered structure. The g-C₃N₄-based low-dimensional heterostructures demonstrate various mechanisms for photogenerated charge carrier transfer including type I heterojunction, type II heterojunction, p–n heterojunction, Z-scheme heterojunction, Schottky junction, and surface plasmon resonance (SPR) effect. Herein, the state-of-the-art g-C₃N₄-based low-dimensional heterostructure photocatalysts are analyzed to provide an insightful outlook with respect to doping and defect engineering, band structures tuning, and charged carrier dynamics to realize enhanced visible light absorption, improved photoinduced charge carrier transport/transfer, and spatially separated electron–hole pairs for improved photocatalytic performances. Furthermore, the potential application of g-C₃N₄-based low-dimensional heterostructures for water splitting, CO₂ reduction, and pollutant degradation is also presented. Finally, conclusion and invigorating perspective about challenges and opportunities for advanced design of g-C₃N₄-based low-dimensional heterostructures are briefed.