Enhanced Photocatalytic Performance of B/P Doped g-C3N4 for Pollutant Degradation: First-Principles Calculation Study

Graphitic carbon nitride (g-C₃N₄) is a visible light catalyst with considerable potential, offering broad application prospects in fields such as pollutant decomposition. In this study, we systematically investigated the geometric, electronic, and optical properties of B-doped, P-doped, and B/P co-doped g-C₃N₄ using first-principles methods. We also examined the adsorption effects of g-C₃N₄ on emerging oxidants, periodate (PI) and Peroxymonosulfate (PMS). The results showed that B/P co-doping significantly narrowed the band gap of g-C₃N₄ to 0.39 eV, transforming it into a direct band gap structure. Additionally, the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) exhibit enhanced delocalization, particularly over the bridging N1 atoms, which improved carrier mobility. Compared to pristine g-C₃N₄, the optical absorption demonstrated a more favorable response to visible light. Notably, the B/P co-doping system significantly increased the adsorption capacity of g-C₃N₄ for PI and PMS, promoting the generation of reactive species such as singlet oxygen (¹O₂), sulfate radicals (SO·₄⁻), and hydroxyl radicals (·OH), providing a favorable pathway for the degradation of pollutants in water. In summary, B/P co-doping significantly enhances the photocatalytic performance of g-C₃N₄, establishing it as a highly efficient, eco-friendly, and cost-effective metal-free photocatalyst with great potential for advanced oxidation processes under visible light in wastewater treatment.

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