Novel feathery P/S Co-doped graphitic carbon nitride for highly efficient synergistic photocatalytic H2O2 generation and tetracycline degradation

Abstract

Graphitic carbon nitride (g-C₃N₄) has garnered significant attention in photocatalytic pollutant degradation for its non-toxicity and cost-effectiveness. However, its limited photocatalytic performance has hindered its applications. Addressing this, we successfully synthesized a novel feathery multifunctional catalyst, phosphorus and sulfur co-doped g-C₃N₄ (P_0.3S_0.2-CN), with an enlarged pore network through a hydrothermal method. This catalyst exhibits remarkable photocatalytic performance under visible light, achieving a hydrogen peroxide (H₂O₂) production rate of 28.6 mg L⁻¹ h⁻¹ and an efficiency of 87.3% in degrading tetracycline (TC). Comparative studies demonstrate that P_0.3S_0.2-CN outperforms singly doped catalysts P_0.5-CN and S_0.4-CN by increasing H₂O₂ yield by 28.67% and 53.28% and improving TC degradation by 15.2% and 11.5%, respectively. These improvements can be attributed to the synergetic effects of P and S co-doping and the high number of active sites provided by its peculiar morphology, which enhance charge transfer and photocatalytic activity, and a more pronounced conjugation effect, resulting in a high electrostatic potential surface conducive to adsorption and activation, as confirmed by density-functional theory calculations. Our findings propose a mechanism for the synergistic photocatalytic-Fenton degradation (PSF) of TC using P_0.3S_0.2-CN. This present research contributes to the advancement of g-C₃N₄-based photocatalysts and promotes the exploration of more efficient carbon-based catalysts for environmental remediation.