Hierarchical Design of 2D Carbon Nitride and Derivatives for Next‐Generation Energy Conversion and Storage Technologies

Two‐dimensional graphitic carbon nitride (2D g‐C 3 N 4 ) has attracted extensive attention in energy conversion and storage due to its unique visible‐light response, tailorable band gap, favorable electrical properties, facile functionalization, and high physicochemical stability. However, there are few reviews on the comprehensive applications of 2D g‐C 3 N 4 and its derivatives for energy conversion and storage. To address this gap, this review provides an in‐depth examination of the structural features and physicochemical properties of g‐C 3 N 4 . Subsequently, a critical analysis of the synthesis and modification strategies of 2D g‐C 3 N 4 and its derivatives is presented. The study investigates the rational design and applications of these materials in various energy conversion and storage systems, including catalysis, batteries, supercapacitors, solar cells, fuel cells, and biomass valorization. Finally, this review discusses the existing challenges and future prospects of employing 2D g‐C 3 N 4 in energy conversion and storage, offering valuable insights for developing next‐generation energy technologies.