Green Synthesis of Zinc Oxide Nanoparticle Using Green Tea Leaf Extract for Supercapacitor Application

Abstract

The advancement of green chemistry in the synthesis of nanoparticles with the use of plants and its parts has become a great attention today. The nanoparticles of metals and metal oxides with green synthesis have reputation on recent developments. Products from nature or that resultant from natural products, such as extracts of various parts of plants have been used as reductions and as ceiling agents during synthesis. In our work, we have chosen green tea leaves(Camellia sinensis) for the Green synthesis of Zinc oxide nanoparticles (ZnO Nps). The formation of nanoparticles was observed by visualizing color changes and it was confirmed by Scanning Electron Microscope (SEM), UV-Vis spectrophotometer and Fourier Transform Infra-Red (FT-IR) spectrophotometer. The results of various techniques confirmed the presence of Zinc oxide nanoparticles. The UV-Vis spectrum was recorded to observe the absorption spectra, which exhibited a blue shift absorption peak at 338 nm. The XRD pattern revealed well-defined peaks appearing at 2θ positions corresponding to the hexagonal wurtzite structure of ZnO nanoparticles. The average size of the nanoparticles calculated using XRD data was 54.84 nm, the band gap energy was 3.40eV. FT-IR spectra were recorded for the as prepared nanoparticle to identify the biomolecules involved in the synthesis process. The higher percentage of phenolic compounds, with antioxidant potential, acts as the reducing agent on the metal oxides and significantly present amino acid, protein and lipids helped to control the growth of the nanoparticles. CV study shows an excellent capacitance behaviour, low equivalent series resistance (ESR) and fast diffusion of electrolyte ions into the composite. This confirms that the as-prepared ZnO material is the best suitable material for supercapacitor applications.