Synthesis and characterization of layered zinc hydroxychlorides
Synthesis and characterization of layered zinc hydroxychlorides
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DOI：
10.1016/j.jssc.2007.05.001
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发表时间：
2007-07-01
影响因子：
3.3
通讯作者：
Ishikawa, Tatsuo
中科院分区：
文献类型：
--
作者：
Tanaka, Hidekazu;Fujioka, Akiko;Ishikawa, Tatsuo
以ZnO纳米粒子为原料，在6 ~ 140℃的不同温度下时效48h，合成了碱式锌盐（BZS）之一的羟基氯化锌层状材料(Zn-5(OH)（8)Cl-2中心点nH(2)O: ZHC）。x射线衍射（XRD）结果表明，在6℃时效后ZnO的衍射峰完全消失，出现了ZHC峰。通过提高时效温度，层状结构的结晶度得到改善。在6℃时，ZHC颗粒为薄的六角形板状颗粒，尺寸为1 ~ 3pm。zc的粒径与时效温度无关。所有材料的Cl/Zn原子比值均接近0.2，小于理论比值的0.4，表明合成的ZHC是缺Cl的。似乎层中一半的Cl原子被HCO $$((3)) / bar和/或OH-取代。根据N-2吸附等温线估计的ZHC的比表面积约为10m(2)g-1，与老化温度无关。然而，所有样品的单位表面积H2O单层吸附容量（n(w)）均高于ZnO颗粒，表明ZHC对H2O分子具有较高的亲和力。通过降低ZHC的结晶度，提高了n(w)值。H2O吸附选择性的增强被认为与颗粒中较少结晶的部分有关。(c) 2007爱思唯尔公司版权所有。
Layered material of zinc hydroxychlorides (Zn-5(OH)(8)Cl-2 center dot nH(2)O: ZHC), which is one of the basic zinc salts (BZS), was synthesized from ZnO nano-particles aged with aqueous ZnCl2 solutions at different temperatures ranging from 6 to 140 degrees C for 48h. X-ray diffraction (XRD) results indicated that the diffraction peaks of ZnO completely disappeared by aging at 6 degrees C and the ZHC peaks were developed. By increasing the aging temperature, crystallinity of the layered structure was improved. At 6 degrees C, the ZHC particles were thin hexagonal plate particles with sizes ranging from I to 3 pm. The particle size of ZHC was independent of aging temperature. The atomic Cl/Zn ratios of all the ZHC materials were almost 0.2 less than 0.4 of the theoretical ratio, indicating that the synthetic ZHC is Cl-deficient. It seemed that half of Cl atoms in the layer were replaced with HCO $$((3)) over bar and/or OH-. The specific surface areas of ZHC estimated from N-2 adsorption isotherms were ca. 10m(2)g-1 and were independent of the aging temperature. However, the H2O monolayer adsorption capacity per unit surface area (n(w)) for all the samples was higher than that of ZnO particles, revealing the high affinity of ZHC to H2O molecules. The n(w) values were increased by reducing the crystallinity of ZHC. This enhancement of H2O adsorption selectivity was thought to be related with less-crystallized parts of the particles. (c) 2007 Elsevier Inc. All rights reserved.