In situ dielectric measurements of Zn-Al layered double hydroxide with anionic nitrate ions

Zn-Al-NO3 layered double hydroxide (Zn-Al-NO3-LDH) was prepared by the co-precipitation method with a ratio of Zn/Al = 4 and at a constant pH of 7. Powder XRD patterns showed the characteristic peaks of layered structure of the LDH sample. Thermogravimetric analysis (TGA) and infrared spectra of the sample were investigated. Because of the existence of water molecules and anionic NO3- in the interlayer of the LDH, the in situ dielectric spectroscopy of the LDH can be described by an anomalous low frequency dispersion using the second type of Universal Power Law. Novel measurements of activation energy of LDH have been obtained at five different frequencies. The energy value increased from 0.05 eV at 1 MHz to 0.37 eV at 134 Hz. The conductivity spectra of sample were studied as a function in temperature of the in situ measurements. The ionic conductivity (dc) of LDH increased as the in situ temperature increased. (C) 2012 Elsevier Masson SAS. All rights reserved.