Synthesis, characterization and proton transport properties of mixed metal phosphonate-zirconium titanium hydroxy ethylidene diphosphonate

Abstract

Novel hybrid material, zirconium titanium hydroxy ethylidene diphosphonate (ZTHEDP) of the class of tetravalent bimetallic acid (TBMA) salt was synthesized using sol-gel route. ZTHEDP was characterized for elemental analysis (zirconium, titanium and phosphorus by ICP-AES and carbon and hydrogen by CHN analyzer), spectral analysis (FTIR), thermal analysis (TGA), Xray diffraction studies and SEM. Chemical resistivity of this material was assessed in various media-acids, bases and organic solvents. The protons present in the structural hydroxyl groups in ZTHEDP indicate good potential to exhibit solid state proton conduction. The proton transport property of ZTHEDP was explored by measuring specific conductance at different temperatures in the range of 303-423 K at 10 K intervals, using Solartron Impedance Analyzer (SI 1260) over a frequency range 1 Hz-32 MHz at a signal level below 1 V. Zirconium hydroxy ethylidene diphosphonate (ZrHEDP) and titanium hydroxy ethylidene diphosphonate (TiHEDP) were also synthesized under identical conditions, characterized and their proton transport properties investigated for comparative studies. It is observed that, in all cases, conductivity decreases with increasing temperature. Conductivity performance of ZTHEDP, ZrHEDP and TiHEDP is discussed based on conductivity data and activation energy. It is observed that, ZTHEDP exhibits enhanced conductance and the mechanism of transportation is proposed to be Grotthuss type.

Synthesis, Characterization, and Proton Conduction Behavior of Thorium and Cerium Phosphonates

“…The acidic character of the coordinated metal ions is related to ionic radii, charge, and coordinate site (phosphonic acids). Zr 4+ (0.86 Å) and Ti 4+ (0.74 Å) with smaller ionic radii and hence a high charge density shows higher proton conduction compared to cerium- and thorium-phosphonates (the bigger the cation, the higher the proton conductivity). , The observed specific conductivity trend is ZrHEDP (4.13 × 10 –4 ) > TiHEDP (1.34 × 10 –4 ) and ThHEDP (5.39 × 10 –6 ) > CeHEDP (8.30 × 10 –7 ). Further, the obtained E a values for ThHEDP (0.68 kcal·mol –1 ) and CeHEDP (0.14 kcal·mol –1 ) are a result of the contribution of such factors as discussed earlier in the text and low compared to ZrHEDP (2.36 kcal·mol –1 ) and TiHEDP (2.87 kcal·mol –1 ) .…”

“…The reports also demonstrate the way to investigate novel proton-conducting materials and to understand the conduction mechanism is now a prior demand, the promising use of these materials being in catalysis, fuel cells, sensors, and so forth. Earlier, we prepared amorphous M 4+ -phosphates and -phosphonates (M = Zr, Sn, and Ti) and studied their proton conduction behavior. ,− Literature survey shows that not much research has focused toward phosphonates of thorium (Th 4+ ) and cerium (Ce 4+ ). In our earlier report, we synthesized thorium and cerium phosphates and measured proton conductivity, where fairly good conductivity was observed in the range of ∼10 –7 S·cm –1 .…”

Giant zirconium-bisphosphonate nano-ribbons and their liquid crystalline phase behaviour in water

“…Products were claimed for the cleansing, polishing and pretreatment of metals as well as their application in adhesives, personal care products, pharmaceuticals, construction materials, fracturing fluids and dental implants. Furthermore, reaction products from zirconyl chloride with HEDP have been proposed as sorbents, 2 ion exchangers, 3,4 catalysts, [5][6][7] proton conductors 8 and recently as corrosion inhibitors for magnesium. 9 The complexation of zirconium from ZrOCl 2 with HEDP has been studied by Romanova et al by using titration and pH.…”

The crystallisation of copper(ii) phenylphosphonates

“…[6][7][8][9] The materials can be used as proton conductors and for the modification of surfaces because of their polar pores and different organic groups. [10][11][12][13][14][15][16] Zirconium(IV) phenylphosphonate was one of the first described metal phosphonates. 17 Cunningham et al showed different syntheses of divalent metal phenylphosphonates with the general formula M(II)(O 3 PC 6 H 5 )•H 2 O.…”