Ag and Fe₃O₄ Comodified WO_{3 – <i>x</i>} Nanocomposites for Catalytic Photothermal Degradation of Pharmaceuticals and Personal Care Products

Abstract

Ag/Fe3O4/WO3 – x nanocomposite photocatalysts, which consist of surface plasmon nanoparticle Ag, magnetically recoverable Fe3O4, and coral-like WO3 – x, are constructed via two-step hydrothermal and photodeposition processes. The significantly strengthened photothermal catalytic-Fenton degradation performance under light irradiation is attributed to the formation of a hierarchical structure, as follows: (i) the unique 3D coral-like defective WO3 – x nanorods possess the inherent properties of charge separation and can provide adequate surface active sites, while incident light is reflected multiple times within the nanorods to enhance light utilization; (ii) efficient photo-Fenton characteristics of Fe3O4 nanomaterials with easy magnetic recovery and fast electron transfer emerging at the intimate interface of Fe3O4 and WO3 – x; and (iii) the surface plasmon resonance (SPR) of Ag nanoparticles and photothermal effects. Radical scavenger experiments and electron spin resonance analysis indicated that •OH and •O2– are the main active species for the removal of broad-spectrum pharmaceuticals and personal care products. Furthermore, a possible photothermal catalytic-Fenton synergistic mechanism is proposed. This study will present novel deep insights into the design of photothermal catalytic-Fenton degradation systems using magnetically Fe3O4 coupled WO3 – x semiconductors and the SPR effect.