Research Article Advanced Materials Science Adv Mater Sci, 2019 doi: 10.15761/AMS.1000147 Volume 4: 1-5 ISSN: 2398-6883 Preparation of various morphologies of ZnO nanostructure through wet chemical methods Nguyen Dac Dien* Vietnam Trade Union University, Dong Da, Hanoi, Vietnam Abstract Hydrothermal route and solution reaction method are adopted for the synthesis of zinc oxide (ZnO) nanopowders having four diferent morphologies such as nanoparticle, mirorod, nanoplate and nanotubule. Zinc nitrate hexahydrate Zn(NO 3 ) 2 .6H 2 O was used as precursor for ZnO nanostructures. ZnO nanorods and nanoplates were synthesized by a hydrothermal approach using KOH as reaction chemical. ZnO nanotubes were obtained by a chemical reaction of Zn(NO 3 ) 2 and NH 4 OH. And ZnO nanoparticles were prepared by precipitation method from zinc nitrate and ammonium carbonate (NH 4 ) 2 CO 3 in aqueous solution. Te structures, morphology, and element components of these ZnO products fabricated by the above-mentioned methods were characterized by X-ray difraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Tese experimental results demonstrated that the as-prepared ZnO nanoparticles have average diameter of 30-60 nm; rod-like ZnO has average diameter of about 350 nm and the length of 3.5 µm; plate-like ZnO has average thickness of about 40 nm and lateral size of 200 × 400 nm; ZnO nanotubules have outer diameter of about 400 nm and inner diameter of about 300 nm, the length of about 4 µm. Te XRD results indicated that four morphologies of ZnO are all wurtzite structure. It is found that the wet chemical technique is very promising for fabricating ZnO nanocrystallines with various morphologies. *Correspondence to: Nguyen Dac Dien, Vietnam Trade Union University, 169 Tay Son, Quang Trung, Dong Da, Hanoi, Vietnam, Tel: 0975528087; E-mail: diennd@dhcd.edu.vn Key words: ZnO nanostructure, precipitation method, hydrothermal treatment, wet chemical technique, characterization Received: December 28, 2018; Accepted: January 18, 2019; Published: January 21, 2019 Introduction ZnO nanostructures have attracted much attention in recent years due to unique optical, electrical properties compared with their bulk counterparts as well as their size-dependent optical and electrical characteristics, which have encouraged many researchers to investigate ZnO nanomaterials. Te properties of the ZnO nanomaterials strongly depended on the microstructures of the materials such as crystal size, morphology (how the crystals are stacked), orientation, aspect ratio, crystalline density [1]. Nano-sized zinc oxide is frequently studied because of its interest in fundamental science as well its applied aspects in many areas, including chemical sensor [2-7], biosensors [8], photocatalysis [9,10], solar cell [11], electrochemical cells [12], ultraviolet lasers [13-15], light-emitting diodes [16], fat panel displays [17], etc. Hitherto, synthesizing uniform nanosized ZnO material is of great important due to its various attractive properties and potential applications. So various methods have been adopted for the fabrication of ZnO nanostructures such as direct precipitation [18-21], sol-gel [19], hydrothermal method [22,23], wet chemical method [8,24,25], thermal evaporation [7,26], etc. Among these techniques, low-temperature wet chemical processes such as precipitation and hydrothermal methods are cost-efective and excellent routes for synthesizing various nanomaterials. Te precipitation process has been successfully used to design diferent structures of ZnO [27]. Te hydrothermal process is relatively easy to perform and allows us to tailor the morphology of the products by controlling the components of the solution reaction and hydrothermal conditions. Hydrothermal method also provides a low cost and large-scale production. It does not need expensive raw materials and complicated equipment. Tis method shows the reliability, repeatability and simplicity compared with other methods. In recent years, scientists have made some advancement in fabricating metal oxide nanostructures using hydrothermal route. For example, Yani Li et al. prepared tungsten oxide nanorods by microwave hydrothermal method [28], Choong-Yong Lee synthesized WO 3 hollow microspheres by one-pot hydrothermal reaction of an aqueous solution containing glucose and sodium tungstate [29], Xuchun Song et al. fabricated tungsten oxide nanobelts by hydrothermal technique using CTAB as assisting agent [30], Jun Zhang et al. synthesized α-Fe 2 O 3 @ZnO core-shell nanospindles via a two-step hydrothermal approach [31], O. Lupan and his colleagues obtained SnO 2 nanorods via a hydrothermal treatment [32], ZnO nanorods and nanoparticles have been synthesized by hydrothermal technique [33], iron oxide was prepared through microwave hydrothermal route using ferrous sulphate and sodium hydroxide as starting chemicals [34]. Various metal oxides were also synthesized by hydrothermal methods such as Sn 3 O 4 [35], FeWO 4 [36], TiO 2 [37,38], ZrO 2 [39], etc. As the morphology and structure of a material depend upon synthesis conditions and parameters, therefore, various precursors and additives are used in aqueous medium to successfully synthesize ZnO nanostructures bearing diferent geometries. It is suggested that the growth mechanism of the ZnO nanostructures is self-aggregation and oriented aggregation. In the present study, the nano-sized ZnO structures were synthesized by a direct precipitation method and a hydrothermal method. Tese methods in comparison with the other methods have their own advantages such as low-processing cost, high quality and high manufacture yield. A detailed comparison of