A Quick Process for Synthesis of ZnO Nanoparticles with the Aid of Microwave Irradiation

Reaction between sodium hydroxide and zinc acetate leads to the formation of zinc hydroxide, Zn(OH)2. The as-prepared Zn(OH)2 was then decomposed by using conventional heating process or with the aid of microwave irradiation. The nanoproducts of both methods were ZnO nanostructures of different size and shape, but the microwave irradiation method shows many advantages in yield and reaction time. Some surfactants such as SDS, CTAB, or PVP were then used to cap the product for studying the influence on the morphology and properties of the nanostructures. 1. Introduction Zinc oxide has been famous for a wide range of applications in the functional devices, photo-catalysts, optical materials, cosmetics, nanostructure varistors, UV absorbers, gas sensors, and industrial additives [1–5]. Until now, many different methods have been developed for the production of ZnO nanopowders [1–3, 6–10]. Mechanochemical processing, sol-gel, or hydrothermal processing methods constitute pertinent examples. However, many of these methods, or at least some of their varieties, are overly costly and constitute demonstrations of laboratory interest only. Nowadays, microwave energy has become a very efficient means of heating reactions. Chemical reactions that took long time to complete can now be accomplished in minutes with the aid of microwave [8–12]. Microwave assisted synthesis not only helped in implementing GREEN chemistry but also led to the revolution in organic synthesis. Microwave irradiation is well known to promote the synthesis of a variety of compounds, where chemical reactions are accelerated because of selective absorption of microwave by polar molecules. In this paper, we report an effective method for the preparation of ZnO nanoparticles by using microwave irradiation. The microwave irradiation method considered herein is fast, mild, energy-efficient, and environment-friendly and, hence, it is not a weak substitute of the conventional method. 2. Experimental Synthesis of ZnO nanopowders was achieved by dissolving 0.1？mol zinc acetate (Merk, 99% purity) in propanol 2 to make 50 mL solution of 0.2？M Zn(CH3COO)2 (Merk, 99% purity). While stirring, 50？mL of 0.3？M NaOH in propanol 2 (Merk, 99% purity) was added dropwise. The resulting solution was then heated to obtain ZnO nanoproduct. To clarify the advantages of microwave irradiation, the above solution was heated in two different ways: heating with microwave oven system (Figure 1) or normal heating with an electric cooker. Figure 1: Image of microwave irradiation system. For microwave heating, the mixture of