Emerging Trends of g-C3N4-Based Photocatalysts from 2020 to 2025

• • Sulfur-doped g-C3N4/TiO2 S-scheme heterojunctions with 3D ordered macroporous structure achieve efficient H2O2 production in pure water, demonstrating the effectiveness of heterostructure engineering for solar-to-chemical conversion. • • B-doped g-C3N4 hierarchical architectures exhibit excellent photocatalytic H2O2 production and photoelectrochemical water splitting, highlighting the role of elemental doping in enhancing multifunctional performance. • • Construction of g-C3N4 with three-coordinated nitrogen (N3C) vacancies significantly enhances photocatalytic activities for N2 fixation and H2O2 production, underscoring the importance of defect engineering in catalytic mechanisms. • • Pt/g-C3N4 Schottky junction photocatalysts show enhanced visible-light H2O2 production, illustrating the impact of cocatalyst loading on charge separation and surface reactivity.