Synergistic engineering of C3N4 Nanosheets via thermal etching and hydrothermal pretreatment for superior photocatalytic hydrogen production and pollutant removal

This study presents a hydrothermal-thermal etching strategy to synthesize layered C₃N₄ nanosheets , to address the structure collapse limits of conventional calcination . The synergistic method retains the layered architecture while boosting surface area (136.5 m 2 ·g −1 ) and porosity. Optimized C₃N₄(H)-6 h nanosheets demonstrate a 5-fold enhanced hydrogen evolution rate (450 μmol·h −1 ·g −1 ) and 97.6 % methylene blue degradation under visible light, outperforming bulk C₃N₄. Superior performance stems from improved charge separation, extended carrier lifetime, and enriched active sites. This scalable approach advances high-efficiency, solar-driven photocatalysts for sustainable energy conversion and environmental remediation. • C₃N₄(H)-6 h nanosheets exhibit a specific surface area 14.5 times higher than bulk materials. • C₃N₄(H)-6 h shows a high hydrogen evolution rate under visible light. • C₃N₄(H)-6 h achieves high degradation rates for methylene blue, methyl orange and rhodamine B.