Ag-single atoms modified S1.66-N1.91/TiO2-x for photocatalytic activation of peroxymonosulfate for bisphenol A degradation

In this study, Ag_0.23/(S_1.66-N_1.91/TiO_2-x) single-atom photocatalyst was synthesized by in-situ photo-reducing of silver on S,N-TiO_2-x nanocomposite and used to degrade bisphenol A (BPA) through heterogeneous activation of potassium peroxymonosulfate (PMS) under visible-light illumination. The structure, physicochemical property, morphology, and electronic property were evalutated by X-ray diffraction (XRD), Raman spectrum, X-ray photoelectron spectra (XPS), high-resolution transmission electron microscopy (HR-TEM), UV–vis diffuse reflectance spectra (UV-vis DRS), electron paramagnetic resonance (EPR) spectrum. Ag_0.23/(S_1.66-N_1.91/TiO_2-x) single-atom photocatalyst exhibited 2.4 times higher activity for the synergetic degradation of BPA than that of its counterpart, and 48.73% mineralization rate of BPA also achieved. It was ascribed to the uniformly-dispersed metallic Ag atoms as the active site for accelerating the migration rate of photo-generated carrier for generation of high reactive radicals. The EPR experiments indicated that SO₄^?? and ^?OH was jointly involved in BPA degradation.