Graphitic carbon nitride with different dimensionalities for energy and environmental applications

As a metal-free semiconductor, graphitic carbon nitride (g-C₃N₄₎ has received extensive attention due to its high stability, nontoxicity, facile and low-cost synthesis, appropriate band gap in the visible spectral range and wide availability of resources. The dimensions of g-C₃N₄ can influence the regime of the confinement of electrons, and consequently, g-C₃N₄ with various dimensionalities shows different properties, making them available for many stimulating applications. Although there are some reviews focusing on the synthesis strategy and applications of g-C₃N₄, there is still a lack of comprehensive review that systemically summarises the synthesis and application of different dimensions of g-C₃N₄, which can provide an important theoretical and practical basis for the development of g-C₃N₄ with different dimensionalities and maximises their potential in diverse applications. By reviewing the latest progress of g-C₃N₄ studies, we aim to summarise the preparation of g-C₃N₄ with different dimensionalities using various structural engineering strategies, discuss the fundamental bottlenecks of currently existing methods and their solution strategies, and explore their applications in energy and environmental applications. Furthermore, it also puts forward the views on the future research direction of these unique materials.