Effect of water vapor on the thermal decomposition process of zinc hydroxide chloride and crystal growth of zinc oxide

Journal Article · Tue Mar 15 00:00:00 EDT 2011 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2011.01.015· OSTI ID:21504054

Kozawa, Takahiro; Onda, Ayumu ^[1]; Yanagisawa, Kazumichi ^[1]; Kishi, Akira; Masuda, Yasuaki ^[2]

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1. Research Laboratory of Hydrothermal Chemistry, Faculty of Science, Kochi University, 2-5-1 Akebono-cho, Kochi 780-8520 (Japan)
2. Rigaku Corporation, 3-9-12 Matsubara-cho, Akishima-shi, Tokyo 196-8666 (Japan)

Thermal decomposition process of zinc hydroxide chloride (ZHC), Zn{sub 5}(OH){sub 8}Cl{sub 2}.H{sub 2}O, prepared by a hydrothermal slow-cooling method has been investigated by simultaneous X-ray diffractometry and differential scanning calorimetry (XRD-DSC) and thermogravimetric-differential thermal analysis (TG-DTA) in a humidity-controlled atmosphere. ZHC was decomposed to ZnO through {beta}-Zn(OH)Cl as the intermediate phase, leaving amorphous hydrated ZnCl{sub 2}. In humid N{sub 2} with P{sub H{sub 2O}}=4.5 and 10 kPa, the hydrolysis of residual ZnCl{sub 2} was accelerated and the theoretical amount of ZnO was obtained at lower temperatures than in dry N{sub 2}, whereas significant weight loss was caused by vaporization of residual ZnCl{sub 2} in dry N{sub 2}. ZnO formed by calcinations in a stagnant air atmosphere had the same morphology of the original ZHC crystals and consisted of the c-axis oriented column-like particle arrays. On the other hand, preferred orientation of ZnO was inhibited in the case of calcinations in 100% water vapor. A detailed thermal decomposition process of ZHC and the effect of water vapor on the crystal growth of ZnO are discussed. -- Graphical abstract: Thermal decomposition process of zinc hydroxide chloride (ZHC), Zn{sub 5}(OH){sub 8}Cl{sub 2}.H{sub 2}O, has been investigated by novel thermal analyses with three different water vapor partial pressures. In the water vapor atmosphere, the formation of ZnO was completed at lower temperatures than in dry. Display Omitted highlights: > We examine the thermal decomposition of zinc hydroxide chloride in water vapor. > Water vapor had no effects on its thermal decomposition up to 230 {sup o}C. > Water vapor accelerated the decomposition of the residual ZnCl{sub 2} in ZnO. > Without water vapor, a large amount of ZnCl{sub 2} evaporated to form the c-axis oriented ZnO.

• OSTI ID: 21504054
• Journal Information: Journal of Solid State Chemistry, Vol. 184, Issue 3; Other Information: DOI: 10.1016/j.jssc.2011.01.015; PII: S0022-4596(11)00016-8; Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CALCINATION
CALORIMETRY
CONTROLLED ATMOSPHERES
CRYSTAL GROWTH
DIFFERENTIAL THERMAL ANALYSIS
EVAPORATION
GRAIN ORIENTATION
HYDROLYSIS
MORPHOLOGY
PARTIAL PRESSURE
THERMAL GRAVIMETRIC ANALYSIS
WATER VAPOR
X-RAY DIFFRACTION
ZINC CHLORIDES
ZINC HYDROXIDES
ZINC OXIDES
ATMOSPHERES
CHALCOGENIDES
CHEMICAL ANALYSIS
CHEMICAL REACTIONS
CHLORIDES
CHLORINE COMPOUNDS
COHERENT SCATTERING
DECOMPOSITION
DIFFRACTION
FLUIDS
GASES
GRAVIMETRIC ANALYSIS
HALIDES
HALOGEN COMPOUNDS
HYDROGEN COMPOUNDS
HYDROXIDES
LYSIS
MICROSTRUCTURE
ORIENTATION
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
PYROLYSIS
QUANTITATIVE CHEMICAL ANALYSIS
SCATTERING
SOLVOLYSIS
THERMAL ANALYSIS
THERMOCHEMICAL PROCESSES
THERMODYNAMIC PROPERTIES
VAPORS
ZINC COMPOUNDS
ZINC HALIDES