Synergistic PMS activation by SnBi@ZrC under visible light for enhanced organic pollutant removal

To enhance the photocatalytic degradation of organic pollutants in peroxymonosulfate (PMS)-based systems, constructing heterojunctions by combining multiple semiconductors has proven more effective than single-component catalysts. In this study, a SnBi@ZrC nanocomposite was synthesized via a hydrothermal method and employed as a visible-light-responsive photocatalyst for PMS activation to degrade Rhodamine B (RhB). Optimal degradation was achieved at neutral pH using 0.45 g L −1 PMS and 0.3 g L −1 SnBi@ZrC, resulting in 98.12 % RhB removal within 20 min, with a reaction rate constant of 0.198 min −1 . Compared to pristine ZrC, the SnBi@ZrC heterojunction exhibited superior photocatalytic activity, attributed to its larger surface area (38.24 m 2  g −1 ), mesoporous structure (12.83 nm), and narrower band gap (1.63 eV), which collectively enhanced light absorption and charge separation. Reactive species quenching experiments confirmed the involvement of SO 4 •− , • OH, O 2 •− , and h + in the degradation process. The SnBi@ZrC catalyst also demonstrated excellent stability and reusability across four successive cycles. Based on experimental results, a possible degradation pathway and mechanism were proposed. These findings suggest that SnBi@ZrC nanocomposites hold significant promise for practical applications in wastewater treatment, particularly for the removal of dye-based and other organic contaminants under visible-light irradiation.