Biomass-engineered graphitic carbon nitride: Structure modulation, charge dynamics, and photocatalytic applications

Graphitic carbon nitride (g-C 3 N 4 ) is a metal-free, environmentally sustainable semiconductor photocatalyst characterized by its well-defined layered structure, tunable electronic structure, and exceptional optical properties. To address the inherent limitations of g-C 3 N 4 that impede its practical application and development, researchers have devised diverse modification strategies, spanning nanostructure engineering, elemental doping/defect introduction, and heterojunction construction. This review underscores the multifaceted synergistic effects derived from the structural diversity of biomass during modification processes. These integrate three core components: (i) Utilizing the unique chiral architecture and abundant functional groups for morphological control (ii) Band structure engineering through biomass-derived unique skeletons and multi-element induced defect formation and (iii) Constructing heterojunctions with unique interfacial effects by integrating biomass materials of different dimensional architectures. Furthermore, synergistic modifications enable atomic-scale lattice engineering with capabilities beyond those achievable by traditional inorganic precursors. Subsequently, we also introduce the applications of biomass-derived modifications in regulating g-C 3 N 4 photocatalysts toward addressing energy conversion and environmental remediation challenges. Finally, we delineate the promising trajectory of biomass-engineered g-C 3 N 4 photocatalysts, envisioning their expanded deployment in energy conversion systems through synergistic integration with emerging technologies. This review systematically consolidates high-efficiency modification strategies for graphitic carbon nitride (g-C 3 N 4 ) mediated by biomass-derived substances, with a focus on the precision engineering of g-C 3 N 4 by biomass-derived molecular. Concurrently, it delineates pivotal challenges and emergent opportunities in biomass- engineered g-C 3 N 4 photocatalysts. • Various synthetic strategies of g-C 3 N 4 nanomaterials are reviewed. • Four biomass modification strategies for g-C 3 N 4 are discussed. • Applications of biomass-modified g-C 3 N 4 in photocatalysis are reviewed. • Challenges and prospects for biomass-modified g-C 3 N 4 are examined.