Microwave-assisted synthesis of ZnO nanoparticles using different capping agents and their photocatalytic application

Abstract

This investigation reports the synthesis of ZnO nanoparticles from various sources of zinc salts via a microwave-assisted method. Furthermore, the synthesized ZnO nanoparticles were capped with different capping agents such as sodium hexametaphosphate (SHMP), polyvinylpyrrolidone (PVP), and cetylpyridinium chloride (CPC) to examine the stability and characteristics of ZnO nanoparticles. The synthesized ZnO nanoparticles were characterized with sophisticated analytical techniques such as XRD, FTIR, SEM, UV-vis DRS, Raman, and PL to understand their properties. From these studies, the XRD depicts the decrease in crystallinity of ZnO nanoparticles with the addition of different capping agents, and the morphology of the ZnO nanoparticles was influenced by capping agents as evidenced by SEM. The band gap of the synthesized ZnO nanoparticles is found to decrease with different capping agents confirmed by UV-Vis DRS studies. Furthermore, the photocatalytic degradation performance of the prepared samples is assessed by the degradation of methylene blue under visible light irradiation. The ZnO nanoparticles synthesized from the Zinc nitrate source with SHMP capping agent show a greater extent of photocatalytic degradation efficiency than other Zinc sources. After 60 min of light, MB was observed to have degraded by about 80%, and hence, zinc nitrate is a suitable source to synthesize ZnO.

Keywords: Capping agent; Methylene blue; Microwave; Photocatalytic degradation; Zinc oxide.