Synthesis of ZnO/Ag/ SiO₂ Nanocomposite Using Flame Pyrolysis Method and its Photocatalytic Activity

Abstract

ZnO nanoparticles are semiconductor materials that can act as a photocatalyst to successfully decompose synthetic dye waste. Unfortunately, electron-hole recombination reduces deterioration efficiency. Adding noble metals, such as Ag nanoparticles, to ZnO can boost its photocatalytic activity. The inclusion of SiO2 prevents ZnO from clumping together, resulting in a wider contact area with synthetic dye waste and a better degrading efficiency value. The effects of SiO2 content in ZnO/Ag/SiO2 nanocomposites, ranging from 0 to 5 %wt, on photocatalytic activity have been investigated in this study. The nanocomposites were made in a single step utilizing flame pyrolysis using zinc acetate, AgNO3 and water glass (Na2SiO3) as the precursors. X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV visible spectroscopy were used to characterize the nanocomposites, which were collected using an electrostatic precipitator. The XRD results confirmed the presence of Ag nanoparticle in the produced nanocomposites, with the crystallite size being unaffected by the presence of Ag nanoparticles. EDX mapping and EDX spectroscopy determined the presence of SiO2 in the composite. The maximum photocatalytic performance was achieved when SiO2 was added to ZnO at a concentration of 0.5% wt, with an efficiency of MB degradation under UV irradiation reached up to 48.15 %. The photocatalyst is reasonably stable until the fourth recycles, at which point the degrading efficiency decreases by an average of 3-6%.