Structural study and phase transition investigation in a simple synthesis of porous architected-ZnO nanopowder

Abstract

In this work, zinc oxide powder with a rectangular-shaped porous architecture, made of numerous spherical nanometric particles, was obtained. A simple precipitation/decomposition procedure was used comprising a zinc oxalate intermediate, obtained from zinc sulfate and oxalic acid without any additives. Detailed studies on zinc oxalate dehydration, decomposition and zinc oxide formation, were carried out using in-situ temperature X-ray diffraction and thermogravimetric analysis. During the investigation, the temperature dependence of particle sizes, lattice parameters and crystal structures of ZnC 2 O 4 •2H 2 O, ZnC 2 O 4 and ZnO nanopowders were analyzed from room temperature to 450°C. Structural transitions were also discussed. The structure and morphology of the as-prepared ZnO nanopowder were investigated by electron microscopy and compared to the crystalline rectangular shape of ZnC 2 O 4 •2H 2 O. The calcination temperature, counter ion and precipitate agent were found to be related to the product's shape and diameter. Spherical ZnO nanoparticles with diameters of less than 20 nm and a maximum specific surface of 53 m 2 /g were obtained using this method.

Structural and electrical properties of TiO2/ZnO core–shell nanoparticles synthesized by hydrothermal method

“…It is well known that the anatase-TiO 2 presents a higher bandgap value (3.2 eV) than the rutile-TiO 2 (3.0 eV) [11]. The band gap value of anatase-TiO 2 is almost similar to that of ZnO nanomaterials (3.3 eV) [6]. Also, as in the case of TiO 2 nanomaterials, ZnO nanomaterials are used in many applications such as: gas and humidity sensors, optoelectronic devices, and UV detectors [12].…”

“…The core-shell nanomaterial consists of an inorganic semiconductor matrix covered, generally, with a shell of other metal oxides [2]. TiO 2 /ZnO coreshell nanomaterial presents a high interest due to its potential applications, such as optoelectronic device [3,4], dye-sensitized solar cells (DSSCs) [5], and photocatalysis [6][7][8]. Recently, TiO 2 /ZnO core-shell nanomaterial was used for photocatalytic H 2 production through water splitting [9].…”

Highly basic and active ZnO–x% K2O nanocomposite catalysts for the production of methyl ethyl ketone biofuel

“…TG and DSC profiles of these samples were recorded using a heating rate of 10°C min −1 in dry oxygen flow of 40 ml min −1 as shown in Figure 2A,B. TG profiles show that pure ZnC 2 O 4 ·2H 2 O and the three mixtures decompose first to anhydrous ZnC 2 O 4 , as the main component, in the temperature range of 115–190°C, due to the dehydration process 36 as shown in Equation (): $$${\mathrm{ZnC}}_{2}{{\rm{O}}}_{4}\cdot 2{{\rm{H}}}_{2}{\rm{O}}\to {\mathrm{ZnC}}_{2}{{\rm{O}}}_{4}+2{{\rm{H}}}_{2}{\rm{O}}\uparrow .$$$…”

Detailed microstructure analysis of as-deposited and etched porous ZnO films

“…Nanostructured ZnO is also of particular interest for organic and dye sensitized solar cells [11,12] or photocatalysis process [13] because it can be nanostructured into nanowires and rods, which makes it ideal for infiltration of the absorption layer. ZnO nanostructured materials importance is manifested in many papers that have been issued for its synthesis using numerous soft chemistry pathways, chemical and physical deposition technologies [14][15][16]. Among them, sputtering technic is particularly used to deposit ZnO thin film materials because of its robustness, large-area and high rates manufacturing capabilities [3,6,7,10,17].…”