Combined bulk and surface analysis of the BaCe0.5Zr0.3Y0.16Zn0.04O3 − δ (BCZYZ) ceramic proton-conducting electrolyte

BaCe0.5Zr0.3Y0.16Zn0.04O3 − δ (BCZYZ) has been advocated as a potential high calibre proton conductor, offering the benefits of both stability and increased proton conductivity. In this work we examine the bulk and surface features of the ceramic in its protonated and unprotonated forms. Following protonation, under H2O pressure as low as 60 mbar, Ba rich surface features are observed at the grain boundary regions, where apparently H2O preferentially attacks. Such surface secondary phases are also noted in the Raman data following a higher pressure treatment of 10 bar, appearing into the sample bulk after 30 h at 500 °C. BCZYZʹs stability towards steam is also discussed.