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Electrical conductivity of “hydrogen-reduced” titanium dioxide (rutile)

1984; Elsevier BV; Volume: 45; Issue: 11-12 Linguagem: Inglês

10.1016/0022-3697(84)90026-x

1879-2553

Keu Hong Kim, Eung Ju Oh, Jae Shi Choi,

Advancements in Solid Oxide Fuel Cells

The electrical conductivities of hydrogen-reduced polycrystalline TiO2 samples were measured at temperatures from room to 600°C under partial pressures of oxygen from 10−6 to 10−1atm. Plots of log σ vs 1T at constant partial pressures of oxygen were found to be linear in the high and low temperature regions with transition points appearing at about 520–590 K, and the activation energy obtained from the slopes had an average of 0.50 eV for the high temperature region and 0.19 eV for the low temperature region. Plots of log σ vs log Po2 were found to be linear at given temperatures, with an average slope of −14 in the high temperature region and −16 in the low temperature region. The predominant defect structures appear to be a Ti3. interstitial at higher temperatures and an oxygen vacancy at lower temperatures. From the oxygen pressure dependence of the electrical conductivity, conduction mechanisms are suggested for the two temperature regions.