Anchoring of alkali-activated surface reactive groups: Dual-groups modified K+&Na+- intercalated C3N5 for enhanced photocatalytic H2O2 production

Photocatalytic production of hydrogen peroxide from water is regarded as an environmentally benign technology for energy storage and supply. Herein, a disordered K&Na-C₃N₅ photocatalyst co-intercalated with K⁺&Na⁺ and modified by cyano/hydroxyl groups is successfully fabricated via alkali-activated thermal-polymerization. Alkali activation effectively anchors cyano and hydroxyl active groups on the surface: hydroxyl groups enhance the material's hydrophilicity and promote proton transfer, while cyano groups exhibit electron-attracting characteristics to localize photogenerated electrons. Simultaneously, interlayer intercalation of K⁺&Na⁺ forms electron transport channels, synergistically facilitating surface proton transfer and optimizing charge distribution. This multi-component modification strategy significantly enhances the adsorption capacity of O₂, effectively modulates the 2e⁻ORR pathway, and improves the selectivity of H₂O₂, demonstrating its excellent bifunctional properties. Experimental data show that the optimally alkali-activated K₃&Na₃-C₃N₅ achieves a remarkably high H₂O₂ production rate of 26,920.49 μmol g⁻¹·h⁻¹— a 90.3-fold increase over unmodified C₃N₅. This work pioneers alkali activation as a universal and scalable paradigm for engineering surface-active sites to enable performance amplification through functional group-metal ion cooperativity, and it provides a design blueprint for advanced carbon nitride-based photocatalysts to boost H₂O₂ fuel cell performance.