SiO2@Ag/AgCl: a low-cost and highly efficient plasmonic photocatalyst for degrading rhodamine B under visible light irradiation

Abstract

A series of highly efficient and low cost visible light-driven micro/nano-structure photocatalysts, composed of microstructure SiO₂ spheres and Ag/AgCl nanocomposites with different proportion of AgCl to Ag, have been facilely and controllably fabricated via deposition–precipitation method and in situ oxidation process. The obtained samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive spectrometry (EDS), X-ray photoelectron spectroscopy (XPS) and UV-vis diffuse reflectance spectra (UV-vis-DRS). The as-prepared photocatalysts exhibit wide absorption in the visible light region and display superior photocatalytic activity and excellent stability towards degradation of organic pollutants, i.e., rhodamine B (RhB) compared with commercial TiO₂ (P25) and pure Ag/AgCl under visible light (λ ≥ 420 nm). Furthermore, the molar ratio of AgCl to Ag in the SiO₂@Ag/AgCl composites has an important effect on their photocatalytic performance. The possible mechanism for the enhancement in decomposition of RhB molecules under visible light irradiation is discussed. This work may provide new insights into the fabrication of visible light-driven photocatalysts with low cost and excellent performance and facilitate their practical application in environmental issues.