SnS₂ integrated P-doped g-C₃N₄ with advanced photocatalytic efficiency towards organic pollutants decontamination

In this study, the P doping and SnS₂ deposition was controlled to get SnS₂ integrated P-doped g-C₃N₄ photocatalysts. The prepared photocatalysts were analyzed by XRD, FESEM, HRTEM, PL, UV-DRS, XPS, and Zeta potential emphasizing their crystalline structures, morphological characteristics, charge carrier recombination, band gap energies, chemical compositions, and surface charge. These results confirmed successful P doping by substituting C and formation of heterojunction with SnS₂. Synthesized materials exhibited good photodegradation efficiency towards organic pollutants: the antibiotic ciprofloxacin (CP) and the cationic dye Rhodamine B (RhB). Among the optimized composites, PCSn-5 (containing 5 wt% of SnS₂ on PCN-2, 1 mmol P doped g-C₃N₄) achieved the highest degradation rates, achieving 99.45% degradation of RhB within 100 min and 89.44% degradation of CP within 120 min. P doping introduced new energy levels that significantly enhanced charge separation and heterojunctions formed improved light absorption, thereby enhancing photocatalytic efficiency. Scavenger analysis acknowledge that holes were primarily responsible for RhB degradation, while in CP degradation both superoxide radicals and holes were dominant species. The photocatalytic efficiency of PCSn-5 was assessed at various pH levels exhibited the peak performance at pH 3 for RhB and at neutral pH for CP. The photocatalyst exhibited strong stability with ≈ 2% reduction in efficiency after five cycles for both pollutants. Electrochemical analysis, conducted through Mott-Schottky plots and electrochemical impedance spectroscopy (EIS), revealed increased donor density and reduced charge resistance following the formation of the composites.