Carbon-nitride based advance materials for energy conversion and storage: Recent advances, current challenges, prospects and environmental consequences

Carbon nitride (g-C₃N₄) as a polymeric semiconductor is extensively investigated as a potential next-generation material in the field of catalysis, optoelectronics, energy conversion and storage, thanks to its high physicochemical and thermal stability along with a suitable bandgap energy of 2.6–2.7 eV, as a low-cost material. However, some major bottlenecks, like low surface area, serious irretrievable capacity forfeiture and deprived electrical conductivity, restrict its potential application in energy storage applications. However, several methods of material structures properties to improve its activity with unique morphological characteristics are not sufficiently summarized in the literature yet. Therefore, the present review article is intended to compile data regarding key methods to prepare g-C₃N₄ with different morphological characteristics in detail. Moreover, this review systematically discusses the use of g-C₃N₄ with the latest information for energy conversion and storage applications, especially photocatalytic hydrogen production (PHP), photocatalytic carbon reduction (PCR), different batteries, supercapacitors (SCs), etc., which has not been sufficiently summarized in the literature yet. Finally, key challenges and prospects to prepare properly tuned g-C₃N₄ for energy conversion and storage applications with its environmental consequences are presented in detail.