A comparative study of proton transport properties of metal (IV) phosphates

M(IV) phosphates of the class of tetravalent metal acid (TMA) salts where M (IV) = Zr, Ti, Sn has been synthesized by the sol–gel method. These materials have been characterized for elemental analysis (ICP-AES), thermal analysis (TGA, DSC), X-ray analysis and FTIR spectroscopy. Chemical resistivity of these materials has been accessed in acidic, basic and organic solvent media. The protons present in the structural hydroxyl groups indicates 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 of 30–120°C at 10°C intervals, using a Solartron Dataset impedance analyzer (SI 1260) over a frequency range 1 Hz–10 MHz at a signal level below 1 V. Based on the specific conductance data and the Arrhenius plots, a suitable mechanism has been proposed and conductance performance of ZrP, SnP and TiP compared.