Advancing photocatalytic performance for enhanced visible-light-driven H₂ evolution and Cr(VI) reduction of g-C₃N₄ through defect engineering via electron beam irradiation

Defect engineering has emerged as a strategic approach for optimizing photocatalyst band structures to improve performance. High-energy electron-beam irradiation is a promising method for inducing vacancies and defects in semiconductor materials, providing a rapid and efficient solution. In this study, we used simple electron-beam irradiation to modify g-C₃N₄ photocatalysts, resulting in the rapid formation of nitrogen vacancies within the material. Characterization techniques such as ¹³C-nuclear magnetic resonance, X-ray photoelectron spectroscopy, and electron paramagnetic resonance confirmed the formation of nitrogen vacancies, resulting in an asymmetric charge distribution within the g-C₃N₄ crystal structure. The optimized photocatalyst, gCN-300, exhibited remarkable performance, producing hydrogen at a rate of 750.57 ± 9.9 μmol g^-1h⁻¹ and reducing Cr(VI) by 83.5% within 2 h with long-term photostability. The improved performance was attributed to increased visible-light absorption, a greater number of surface-active sites, improved electronic conductivity, and efficient charge transfer. These factors were supported by UV–visible diffuse reflectance spectroscopy, photoluminescence, and photoelectrochemical analysis. Thus, this study demonstrates the effectiveness of electron-beam irradiation in the large-scale production of defect-engineered photocatalysts with high performance.