Effect of SiO₂ Content on Photocatalytic Activities of ZnO/Ag/SiO₂ Nanocomposites Prepared by Spray Pyrolysis

Spray pyrolysis is a method for preparing nanocomposite materials in the gas phase. Due to the ease with which the temperature in the furnace can be controlled, this method can produce more uniform nanoparticle sizes. This method can be used to synthesize ZnO nanoparticles. Additionally, due to the photocatalytic properties of the synthesized particles, they are used to decompose synthetic dye waste. Due to electron-hole recombination, ZnO's photocatalytic properties are limited. A doping process with various metals was used to enhance the photocatalytic properties of ZnO nanoparticles. Ag is one of these metals. The addition of Ag metal to ZnO nanoparticles results in the formation of nanocomposites with preferable photocatalytic properties. However, the addition of Ag results in the aggregation of the obtained particles. As a result, the ZnO particles must be trapped in a matrix (for example, SiO₂) to inhibit particle growth. This research aims to determine the effect of the SiO₂ composition on the characteristics and photocatalytic properties of ZnO/Ag/SiO₂ nanocomposite synthesized via spray pyrolysis. SEM (Scanning Electron Microscope) analysis was used to determine the morphology of the nanocomposites, XRD (X-ray Diffraction) analysis was used to determine the purity and degree of crystallization, FTIR (Fourier-transform Infrared) analysis was used to determine the functional groups, and UV-Vis Spectrophotometer analysis was used to determine the photocatalytic characteristics. According to the analysis results, the optimal photocatalytic activity was obtained at 1% SiO₂, with a degradation rate of up to 47% of methylene blue and a rate constant (k) of 0.0086 L/min under UV light irradiation.