Construction of Magnetic FeP/CdS Composites as Photo-Fenton-Like Catalysts to Realize High-Efficiency Degradation of Tetracycline Hydrochloride

Abstract

Photocatalysis is an efficient technology for the degradation of pollutants. However, it still needs to be improved. In this study, magnetic Z-scheme FeP/CdS composites heterojunction photocatalysts were prepared by a facile hydrothermal method, and the structure, morphology, optical, and photocatalytic properties of the prepared composites were investigated in detail. The efficiency of tetracycline hydrochloride (TCH) removal by FeP/CdS composites was investigated under different reaction conditions (including different FeP and CdS ratios, catalyst dosage, hydrogen peroxide consumption, temperature, and initial pH). FeP/CdS composites exhibited better catalytic performance compared with pure components. The F₁Cd₁ composite (mass ratio of FeP to CdS is 1:1) achieved 92.7% removal efficiency of TCH; moreover, the F₁Cd₁ composite still exhibits a high stability after five consecutive cycles. The capture experiments on the active material showed that the removal of TCH by the F₁Cd₁ composite was mainly dominated by •OH; however, •O₂⁻, e⁻, and h⁺ played a minor role, and the degradation mechanism was revealed by combining various characterization techniques. The introduction of cadmium sulfide formed an effective photogenerated carrier transport channel at the interface with the iron phosphide surface, which could accelerate the transfer and separation of photo-excited e⁻/h⁺ pairs, thus improving the degradation performance of TCH.