In moist conditions, the ceramic membrane is “hydrated” as protons
are incorporated into the lattice through the Stotz–Wagner mechanism
This hydrogen transport through such a protonic defect is generally
the desired result in most applications. However, in oxidizing atmosphere,
electronic defects of holes are formed as oxygen is incorporated
into the lattice
Recently, it was proposed that these electronic defects are localized on the sites of lattice oxygen, as described in Reaction 4
In addition, significant electronic conduction through high ceriumcontaining
BCZYwhen subjected to reducing atmosphereswas reported. Cerium ions can be reduced to the lower oxidation state of 3+ to
generate electrons