Proton Conductivity and Thermoelectric Effect in Magnesium Hydroxide
- 1 January 1977
- journal article
- research article
- Published by Wiley in Berichte der Bunsengesellschaft für physikalische Chemie
- Vol. 81 (1) , 39-43
- https://doi.org/10.1002/bbpc.19770810111
Abstract
The d.c. conductivity ∑(T) and the thermoelectric effect U(T) of high purity Mg(OH)2 powder were measured under dry N2/H2 gas at atmospheric pressure using Pd/H electrodes. When a field gradient in the order of 104 V / cm is applied, proton conductivity ∑p is observed between 170—240°C with a maximum around 210°C, superimposed to a background conductivity ∑0 of probably electronic nature due to transition metal impurities. The activation energy for the linear portion in the log ∑p vs. T−4 plot was found to be 2.1 eV. The thermoelectric effect U(T) gave positive potentials over the wole temperature range studied which corresponds to a p‐type semiconductor. Again between 170–240 °C a protonic contribution Up was found with a maximum around 225 °C. Its activation energy is also 2.1 eV. The results are consistent with the model of a proton tunnelling mechanism in Mg(OH)2 as a precursor to its decomposition to MgO.Keywords
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