Novel amorphous zirconium (IV) phosphonates of the class of tetravalent metal acid (TMA) salts have been synthesized by sol–gel method where phosphonates used are hydroxy ethylidene diphosphonic acid (HEDP), amino tri(methylene phosphonic acid) (ATMP) and diethylenetriamine penta(methylenephosphonic acid) (DETPMP) to give ZrHEDP, ZrATMP and ZrDETPMP, respectively. These materials have been characterized for elemental analysis, Zr and P (ICP-AES) and carbon, hydrogen, nitrogen contents (CHN analyser), thermal analysis (TGA, DSC), X-ray analysis and FTIR spectroscopy. Chemical resistivity of these materials has been accessed in acids, bases and organic solvent media. The protons present in the structural hydroxyl groups indicate good potential for TMA salts to exhibit solid state proton conduction. The transport properties of these materials has been explored by measuring specific proton conductance at different temperatures in the range 30–120°C at 10°C intervals, using SOLARTRON DATASET impedance analyser (SI 1260) over a frequency range 1 Hz–10 MHz at a signal level below 1 V. Based on the specific conduction data and Arrhenius plots, a suitable mechanism has been proposed and conductance performance of zirconium phosphonates compared with zirconium phosphate (ZrP).
Volume 43, 2020
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