Proton conduction in oxygen deficient Ba3In1.4Y0.3M0.3ZrO8 (M = Ga3+ or Gd3+) perovskites

Journal article, 2014

B-site disordered, oxygen deficient Ba3In1.4Y0.3M0.3ZrO8 (M = Gd3+ or Ga3+) perovskites of space group Pm (3) over barm, were prepared by a solid-state reactive sintering method. Thermogravimetric analysis of the as-prepared samples revealed 79.3% and 55.5% protonation of the available oxygen vacancies by OH groups in the Gd-3: and Ga-3: containing samples, respectively. Conductivity was found to be in the range of 0.3-1.1 x 10 (3) S cm (1) (M = Gd3+) and 1.1-4.6 x 10 (4) S cm (1) (M = Ga3+) for the temperature interval 300-600 degrees C in wet Argon. Ba3In1.4Y0.3Ga0.3ZrO8 shows an approximate one order of magnitude increase in conductivity at T > 600 degrees C under dry oxygen indicating a significant p-type contribution whereas Ba3In1.4Y0.3Gd0.3ZrO8 reveals a smaller enhancement. Ba3In1.4Y0.3Ga0.3ZrO8 displays considerable mixed proton-electronic conduction in the interval 400-800 degrees C under wet oxidising conditions suggesting possibility of Ga-containing compositions as a cathode materials in a proton conducting fuel cell.