Heras Juaristi, GemmaAmador, UlisesFuentes, RodolfoChinelatto, AdilsonRomero de Paz, JulioRitter, ClemensFagg, DuncanPérez Coll, DomingoMather, Glenn2024-02-082024-02-082017Heras-Juaristi, G., Amador, U., Fuentes, R. O., Chinelatto, A. L., de Paz, J. R., Ritter, C., ... & Mather, G. C. (2018). Thermal evolution of structures and conductivity of Pr-substituted BaZr 0.7 Ce 0.2 Y 0.1 O 3− δ: potential cathode components for protonic ceramic fuel cells. Journal of Materials Chemistry A, 6(13), 5324-5334.2050-748810.1039/c7ta09570hhttps://hdl.handle.net/20.500.14352/100226The authors would like to congratulate Professor Tony West on the occasion of his 70th birthday. GCM especially appreciates the invaluable guidance in solid-state chemistry provided to him by Prof. West. This work was supported by the MINECO, Spain (ENE2015-66183-R, MAT2016-78362-C4-1-R), CSIC, Spain (i-link0743), CAPES, Brazil (PVE, Proceso 88881.03418/2013-1) and the FCT, Portugal (POPH, PTDC CTM-EME 6319 2014). Access to the neutron facilities at the Institut Laue Langevin (Grenoble, France) and the National Synchrotron Light Laboratory (LNLS, Campinas, Brazil) under grant 5-24-55(D2B) and research proposal D10B-XRD1-16166, respectively, is gratefully acknowledged. U. A. also thanks the Universidad San Pablo for financial support.A complete solid solution forms between the perovskite proton conductor BaZr0.7Ce0.2Y0.1O3 d (BZCY72) and BaPr0.9Y0.1O3-d (BPY) on synthesis by the Pechini method and high-temperature annealing. Phase fields of selected members of the Ba(Zr0.7Ce0.2)1-(x/0.9)PrxY0.1O3-d series were studied as a function of composition and temperature by high-resolution neutron powder diffraction revealing symmetry changes in the sequence Pnma / Imma / R3c / Pm-3m. Higher symmetry is favoured for low Pr contents and high temperatures, as consideration of tolerance factor suggests. A volume contraction, ascribed to dehydration, is observed by synchrotron X-ray diffraction on heating in air for lower x. Magnetic measurements and structural data support the presence of Pr in the IV valence state on the perovskite B site. Thermogravimetric analysis in CO2 to near 1253 K indicates better chemical stability for x <= 0.445, whereas decomposition occurred for higher x. Electrical conductivity increases by over two orders of magnitude in dry air at lower temperature from x = 0.225 to 0.675; total conductivity reaches a value of 0.4 S cm-1 at 1173 K for x = 0.675. The series exhibits electron–hole transport with a positive pO2 dependence which increases with temperature, consistent with participation of oxygen vacancies in charge compensation of the Y3+ acceptor dopant. The activation energy for thermally activated hole hopping in air in the range 523–773 K decreases from near 1 eV for BZCY72 to near 0.4 eV for x = 0.675. Conductivity is generally lower in humidified N2 and air (pH2O = 0.023 atm) than the corresponding dry atmospheres, consistent with consumption of holes by less mobile protonic species; however for x <= 0.225 the lower concentration of electron holes concomitant with higher oxygen-vacancy content in N2 results in slightly higher conductivity in wet conditions due to hydration of vacancies.engAttribution-NonCommercial-NoDerivatives 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-nd/4.0/journal article2050-7496https://doi.org/10.1039/c7ta09570hmetadata only access546Química inorgánica (Química)2303.26 Estructura de Los Compuestos Inorgánicos2303.24 Tierras Raras2211.26 Dispositivos de Estado Sólido