Ecofriendly Synthesis and Photocatalytic Activity of Uniform Cubic Ag@AgCl Plasmonic Photocatalyst

Abstract

Uniform cubic Ag@AgCl plasmonic photocatalyst was synthesized by a facile green route in the absence of organic solvent, in which a controllable double-jet precipitation technique was employed to fabricate homogeneous cubic AgCl grains and a photoreduction process was used to produce Ag nanoparticles (NPs) on the surface of AgCl. During the double-jet precipitation process, the presence of gelatin and Cl– ions at low concentration was necessary for the formation of cubic AgCl grains. Atomic force microscopy (AFM) was used to probe the morphological structure of Ag@AgCl grains for the first time, which showed that Ag NPs are anchored on the surface of AgCl grains like up-and-down mounds. Further characterization of the photocatalyst was also done by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV–visible diffuse reflectance spectroscopy (DRS). The as-prepared Ag@AgCl plasmonic photocatalyst exhibited excellent photocatalytic efficiency for the degradation of the azo dye acid orange 7 (AO7), phenol, and 2,4-dichlorophenol (2,4-DCP). The photocatalytic mechanism was studied by radical-trapping experiments and the electron spin resonance (ESR) technique with 5,5-dimethyl-1-pyrroline N-oxide (DMPO), and the results indicated that •O2– and Cl0 are responsible for the rapid degradation of organic pollutants under visible-light irradiation.