Photothermal-Assisted Photocatalytic Degradation of Rhodamine B Using Fe 3 O 4 /ZnIn 2 S 4 Type-II Heterojunction: Mechanism and Performance

The increasing severity of wastewater pollution poses a significant environmental challenge, calling for efficient and sustainable treatment strategies. This study reports a solar-driven photothermal catalytic system based on Fe3O4/ZnIn2S4 type-II heterojunctions for efficient degradation of rhodamine B (RhB). In practical solar-light degradation experiments, under sunlight irradiation, the 2-Fe3O4/ZnIn2S4 catalyst generates localized heat, raising the solution temperature by 14.1 °C and achieving a degradation efficiency of 99.4% toward Rhodamine B (RhB) within hours. Electrochemical analyses confirm enhanced charge separation and suppressed electron–hole recombination due to the heterojunction structure. Density functional theory calculations further reveal the degradation pathway and the superior mineralization ability of the catalyst. This approach demonstrates high efficiency and robust applicability, offering a promising strategy for solar-driven wastewater remediation with substantial environmental and practical potential.