Thermionic emission of protons across a grain boundary in 5 mol% Y-doped SrZrO3, a hydrogen pump

Effect of A-Site Nonstoichiometry on Defect Chemistry and Electrical Conductivity of Undoped and Y-Doped SrZrO3

“…At first glance, the low solubility of yttrium in strontium zirconate revealed in the present research does not match the previously reported data [11,13,24,25]. Huang and Petric [11], for example, reported on the formation of single-phase solid solutions in SrZr 1−x Y x O 3−δ synthesized via solid-state reaction and sintered at 1500–1600 °C between x = 0 and 0.2, however, the XRD data were not presented.…”

“…The activation energies of the bulk and grain boundary conductivity are found to depend on Sr content having the lowest value at x = 0.98 and decrease with a rise in water vapor partial pressure as shown in Figure 11. The values of activation energy obtained in the present research are consistent with the reported data for SrZr 0.95 Y 0.05 O 3−δ in wet nitrogen [25] which are also given in Figure 11. The higher values of the activation energy of the grain boundary conductivity comparing to the bulk indicate the existence of an additional energy barrier which can be related with the formation of space charge layers at the grain boundaries [31].…”

“…Thus, the phase composition of SrZrO 3 heavily doped with yttrium appears to be more complicated than expected. Strontium zirconate with a smaller concentration of yttrium was studied in [13,25]. Single crystals of SrZrO 3 nominally doped with 5 mol% yttrium were grown by a floating zone method in an oxygen-containing atmosphere [13].…”

“…Polycrystalline SrZrO 3 doped with 5 mol% yttrium was obtained by Pechini method, the isostatically pressed pellets were sintered at 1700 °C for 20 h in air [25]. XRD pattern obtained in Cu Kα radiation showed a set of peaks characteristic for SrZrO 3 with an orthorhombic structure along with a minor peak at 2θ ~ 29.3° which was ignored.…”

“…The lines between points are only a guide to the eye. Activation energies for SrZr 0.95 Y 0.05 O 3−δ measured in wet nitrogen [25] are given for comparison (red squares).…”