Green synthesis of zinc oxide marigold shaped clusters using Eucalyptus globulus leaf extract as robust photocatalyst for dyes degradation under sunlight

Abstract

This paper reports a facile route to synthesis of zinc oxide (ZnO) nanoparticles assembled into marigold shaped clusters utilizing the Eucalyptus globulus leaf extract. Synthesized ZnO marigold shaped clusters were examined as catalyst for photocatalytic degradation of non-degradable organic dyes under the natural sunlight. The structural properties of as-synthesized ZnO marigold shaped clusters were demonstrated by powder-X-ray diffraction confirming the high crystallinity with hexagonal phase. Moreover, detailed structural and crystallographic analyses for as-synthesized ZnO marigold shaped clusters were analyzed through Rietveld refinement using FULLPROF software which further confirmed the wurtzite-type structure with P63mc space group. Field emission scanning electron microscopy was utilized to investigate the morphology of the synthesized ZnO, which revealed that nanoparticles assembled in clusters and eventually transformed into marigold shaped structures. Transmission electron microscopy analysis demonstrated that as-synthesized ZnO marigold shaped clusters consist of spherical and hexagonal nanoparticles with average crystallite size of 6 ± 2 nm. The role of Eucalyptus globulus leaf extract for the formation of ZnO clusters was discussed in detail by the plausible reaction mechanism. As-synthesized ZnO marigold shaped clusters exhibited the excellent photocatalytic behavior by observing almost 98 % photocatalytic performance towards organic dyes under open air sunlight condition. The aim of such investigation of the synthesized ZnO clusters has potential as solar based photocatalytic application towards efficient degradation of organic dyes.