Trimetallic Au-Ag-Cu Joint Doped Hydroxyapatite: Synergistic Photo-Fenton-Like Catalytic Performance Enhancement.

Photo-Fenton oxidation, as a promising wastewater treatment technology, suffers from double barriers: the sluggish Fenton catalytic rate of transition metal ions and inefficient visible light absorption, both of which severely constrain the performance enhancement of catalytic systems. Therefore, accelerating electron transfer processes and broadening optical absorption spectra have become critical scientific challenges for practical implementation. Herein, a composite catalyst system based on Au-Ag-Cu trimetallic species codoped on hydroxyapatite (HAp) was reported via an ion/ligand impregnation method. AuAgCu/HAp catalyst exhibited superior performance in methylene blue degradation, achieving 100% removal efficiency within 30 min, significantly outperforming mono- or bimetallic doped HAp systems. The exceptional catalytic activity of AuAgCu/HAp likely arises from multimetal synergistic effects that enhance photo-Fenton reactivity, facilitating the generation of diverse reactive species. Notably, singlet oxygen (O) and photogenerated holes (h) were identified as dominant oxidants. This catalyst demonstrated excellent degradation efficiencies toward various organic contaminants, maintained low metal ion leaching concentrations, and retained a high recyclability over multiple cycles. It is expected to have excellent application prospects in actual wastewater treatment.