Synergistic augmentation of dielectric and photocatalytic properties of ZnO via Ag nanoparticle integration

Abstract

This study investigates the effect of Ag incorporation on dielectric and photocatalytic properties of the ZnO matrix. The synthesized samples were characterized using X-ray diffraction (XRD), diffused reflectance spectroscopy (DRS), scanning electron microscopy (SEM), elemental dispersive X-ray spectroscopy (EDX), impedance spectroscopy, and UV–visible infrared spectroscopy. XRD confirmed the successful synthesis of Ag/ZnO nanocomposites without any secondary phase. SEM micrographs showed discs and rods-like morphology of ZnO and Ag NPs, respectively. Furthermore, an increased agglomeration was also observed in the nanocomposite as the concentration of Ag NPs was increased in Ag/ZnO Nanocomposite. The dielectric study revealed that the incorporation of Ag nanoparticles (Nps) increased the dielectric constant of ZnO by 100 times (102 Hz), with minimal tangent loss in Ag/ZnO (20 %). Complex plane plots disclosed the presence of two relaxation processes with different relaxation times in the synthesized samples. The metallic nature of Ag NPs contributed to the reduction of the charge transfer resistance of the nanocomposite. Furthermore, the enhanced dielectric behavior was ascribed to the formation of micro/nano capacitors due to the interaction of conductive Ag NPs with relatively less conducting ZnO grains. The photocatalytic performance of the synthesized nanocomposites was also evaluated for the degradation of methylene blue. The presence of Ag NPs increased the photocatalytic activity due to its enhanced conductivity and sluggish electron-hole recombination. Ag/ZnO (20 %) nanocomposite showed the best photocatalytic activity with a reaction rate of 0.239 min−1. The exceptional dielectric properties demonstrate the potential of Ag/ZnO nanocomposites for low-frequency applications. Furthermore, the enhanced photocatalytic activity of ZnO upon Ag inclusion discloses the potential of the synthesized nanocomposite for water remediation applications.