Departamento de Química Inorgánica, Facultad de Ciencias , Universidad de Málaga , 29071 Málaga , Spain.
Inorg Chem. 2018 Aug 6;57(15):9067-9078. doi: 10.1021/acs.inorgchem.8b01074. Epub 2018 Jul 10.
The conduction and dielectric properties in zinc hydroxide nitrate (ZHN) were studied in detail as a function of the temperature and relative humidity by impedance spectroscopy, and the structure was investigated by X-ray diffraction (XRD). Elemental analysis indicated a layered material containing carbonate anions [Zn(OH)(NO)(CO)·1.7HO] due to the high capability of adsorption of ZHN, which makes this material appropriate for applications in real conditions. The water content affected the interlayer distance, conductivity, and dielectric response of the layered material. An electrostatic repulsive interaction after reduction of the water content as a function of the temperature causes an increase of the interlayer distance and a decrease in the conductivity response and dielectric behavior. The highest conductivity, 10 Ω cm, was obtained at a shorter interlayer distance for the sample heat-treated at 25 °C. The ZHN synthesized was also characterized at different temperatures using thermogravimetric analysis and Fourier transform infrared and Raman spectroscopy. Multipeak analysis of the XRD patterns at various relative humidity levels showed the formation of a most hydrated phase and an increase of the interlayer distance related with the adsorption of water molecules. This layered material presented a conductivity of 10 Ω cm at high relative humidity (92%). The dipole-dipole interaction appeared to be the dominant mechanism for the dielectric behavior at the lowest temperatures and highest humidity due to the high water content in the ZHN structure. Taking into account its crystallization water and high adsorption of water molecules in the interlayer region, a conduction pathway in the ZHN structure was proposed, which provides the route for proton transport by hydrogen-bonding networks on the basis of a Grotthuss-type mechanism in facilitating the long-range proton hopping at 25 °C. The results for high relative humidity imply that a vehicular conduction mechanism also may contribute to the electrical response.
详细研究了作为温度和相对湿度函数的氢氧化锌硝酸盐（ZHN）的传导和介电性能，通过阻抗谱研究了结构，并通过 X 射线衍射（XRD）进行了研究。元素分析表明，由于 ZHN 的高吸附能力，该材料含有碳酸根阴离子[Zn（OH）（NO）（CO）·1.7HO]，这使其适合于实际条件下的应用。水含量会影响层状材料的层间距、电导率和介电响应。水含量降低导致静电排斥相互作用，这会随着温度的升高引起层间距增加、电导率响应和介电行为降低。在 25°C 下热处理的样品的层间距较短，获得了最高的电导率 10 Ω cm。还使用热重分析、傅里叶变换红外和拉曼光谱在不同温度下对合成的 ZHN 进行了表征。在不同的相对湿度水平下对 XRD 图谱进行多峰分析表明，形成了最水合的相，并且由于水分子的吸附，层间距增加。这种层状材料在高相对湿度（92%）下表现出 10 Ω cm 的电导率。由于 ZHN 结构中的含水量高，在最低温度和最高湿度下，偶极-偶极相互作用似乎是介电行为的主要机制。考虑到其结晶水和层间区域中水分子的高吸附性，提出了 ZHN 结构中的传导途径，该途径通过基于 Grotthuss 型机制的氢键网络提供质子传输的途径，从而在 25°C 下促进长程质子跳跃。高相对湿度下的结果表明，载流子传导机制也可能有助于电响应。
