One-step construction of Y, C, and O tridoped g-C₃N₄ as a bifunctional photocatalyst for H₂ evolution and organic pollutant degradation under visible light irradiation

Photocatalytic H₂ production and degradation of pollutants are promising strategies for energy conversion and environmental protection, where highly efficient photocatalysts are required. Herein, a novel type of Y, C, and O tridoped g-C₃N₄ bifunctional photocatalyst was prepared via a simple one-step low-cost thermal polymerization technique, which exhibits a significant enhancement in photocatalytic redox efficiency under visible light for H₂ production and degradation of pollutants compared to bulk g-C₃N₄. The optimized Y0.1/C/O tridoped g-C₃N₄ photocatalyst exhibits a remarkable H₂ evolution rate (HER = 2542.4 μmol g⁻¹ h⁻¹) which is 5 times higher than that of pristine g-C₃N₄ with a high apparent quantum yield of 6% at 420 nm, besides excellent degradation efficiencies for organic pollutants (∼100, 98.5 and 82.4% for mixed dyes, congo red, and methylene blue, respectively). The influence of Y³⁺ concentration on the photocatalytic performance and electronic structure of Y/C/O-CN was also investigated. The major reactive species involved in the photodegradation process were found to be superoxide (O₂˙⁻) radicals. Moreover, the experimental and computational results suggest that the enhanced photocatalytic performance is due to the synergistic effect of Y, C, and O tridoping, which can adjust the band structure of g-C₃N₄, reduce the bandgap, improve visible-light absorption, and accelerate charge separation. This study paves the way to fabricate extremely effective tridoped photocatalysts for efficiently evolving hydrogen under visible light and resolving future environmental pollution.