Iron Phosphate Nanomaterials for Photocatalytic Degradation of Tetracycline Hydrochloride

Four different phosphorous precursors [H₃PO₄, (NH₄)H₂PO₄, (NH₄)₂HPO₄, and (NH₄)₃PO₄] were utilized to study their influence on the physicochemical characteristics and photocatalytic performance of iron phosphate (FeP) nanomaterials. Among the synthesized samples, FeP-H₃ photocatalyst synthesized using H₃PO₄ exhibited superior photocatalytic performance for degradation of aqueous tetracycline hydrochloride (TCH) solution under visible light. The investigation of the influence of photocatalytic reaction conditions revealed that the degradation efficiency of TCH in 5 h was 72% when the dosage of FeP-H₃ catalyst was 120 mg/L; the initial concentration of TCH solution was 15 mg/L; and the initial pH of 10. The phosphorus precursor shows multiple effects on the physicochemical properties of FeP nanomaterial. It is revealed that the FeP-H₃ sample possesses highly crystalline FeP nanosheets with high surface area and low bandgap, resulting in the fast capture of photogenerated electrons and the following generation of O²⁻ radicals. The [PO₄]³⁻and [─OH] groups adsorbed on the surface of FeP can further assist negative electrostatic field, which enhances the separation of photogenerated e⁻-h⁺ pairs, whereby the h⁺ species improve the generation of photoreactive OH radicals. Furthermore, the photocatalytic performance of FeP nanomaterials for degradation of TCH was optimized.