The conductivity of a mesoporous phosphate pyrophosphate, Zr(P2O7)0.81(O3POH)0.38 was determined as a function of temperature in a controlled relative humidity. Alternating- and direct-current conductivity measurements which were carried out in N or H flows, showed that the charge carriers were protons. At 20C, and a relative humidity of 90 to 20%, the conductivity changed from 1.3 x 10-3 to 4 x 10-7S/cm. The activation energy for conduction, at 20 to -20C, increased from 4.6 to 8.7kcal/mol with decreasing relative humidity. At 100C, and 90% relative humidity, the pyrophosphate groups underwent slow rehydration and the conductivity increased to 2.6 x 10-3S/cm; due to an increase in the number of -POH groups.

Proton Conductivity of Mesoporous Zirconium Phosphate Pyrophosphate. G.Alberti, M.Casciola, S.Cavalaglio, R.Vivani: Solid State Ionics, 1999, 125[1-4], 91-7