Various TiO2-coated ZnO samples were prepared by the sol−gel method for use as the anode active materials of Ni−Zn secondary batteries. At a low annealing temperature, the added titanium does not r...

Characteristics and Electrochemical Performance of the TiO2-Coated ZnO Anode for Ni−Zn Secondary Batteries

The synthesis of a ZnO−TiO2 nanocomposite usually results in the formation of one or more of three compounds—Zn2TiO4, Zn2Ti3O8, and ZnTiO3—along with other secondary impurity phases, such as rutile-TiO2 or ZnO. Obtaining a phase-pure composite of either of these materials is one of the challenges in materials chemistry. For example, pure ZnTiO3 cannot be synthesized under normal conditions, because the ZnTiO3 phase readily transforms to Zn2TiO4 and rutile. Zn2Ti3O8 is reported as a metastable form of ZnTiO3. The Zn2TiO4 form is usually synthesized via solid-state reaction at high temperatures (typically above 1000 °C). In the current study, the crystalline and phase-transformation behaviors of sol−gel-synthesized zinc titanates has been investigated systematically, with regard to various Zn:Ti precursor molar ratios. X-ray diffraction (XRD) has shown that, with excess titanium precursor, zinc metatitanate (ZnTiO3) is the preferred zinc titanate phase formed at temperatures of 600−900 °C, with a direct tra...

/pdf/crystallization-and-phase-transition-characteristics-of-sol-1ouu0r5ncy.pdf

Crystallization and Phase-Transition Characteristics of Sol−Gel-Synthesized Zinc Titanates

Zn and Ag Co-doped Anti-microbial TiO2 Coatings on Ti by Micro-arc Oxidation

Nanocrystalline microwave dielectrics ZnTiO3 and Zn2TiO4 (spinel) phase have been prepared by high-energy ball milling the powder mixture of ZnO and anatase (a)-TiO2. Ball milling of equimolar powder mixture of ZnO and a-TiO2 is continued up to 6 h with some intermediate milling steps. Microstructure of all the samples is characterized by Reitveld's structure refinement method using X-ray powder diffraction data. Mixture of nanocrystalline ZnTiO3 and Zn2TiO4 is noticed to form after 6 h of ball milling. Within 30 min of milling formation of Zn2TiO4 is noticed in the X-ray diffraction pattern whereas the formation of ZnTiO3 starts after 2 h of ball milling. The formation mechanism, phase transition kinetics, structure and microstructure changes in terms of lattice imperfections and relative phase abundances of individual phases have been estimated from the analysis of X-ray powder diffraction data of unmilled and ball-milled samples by Rietveld's powder structure refinement method.

Hijili Kito

Papers

Precipitate within the spinel-type Zn2TiO4 matrix studied by high-resolution analytical transmission electron microscopy