Platinum nanoparticle induced nanoionic effects on electrical conduction in strontium cerate and zirconate

Heterointerfaces introduce unique localized defects into ionic conductors. This study explores the nanoionic characteristics exhibited by the proton-conducting oxides SrZr _0.9 Y _0.1 O _3-δ and SrCe _0.95 Yb _0.05 O _3-δ including finely dispersed precipitated platinum nanoparticles. The electrical conductivity of both the platinum-doped oxides revealed reversible nanoionic phenomena caused by the exsolution of the platinum in the form of platinum nanoparticles, at 0.5 vol% relative to the metal oxides, and dissolution in response to a change in gas atmosphere. In comparison with the original conductivity of SrZr _0.9 Y _0.1 O _3-δ and SrCe _0.95 Yb _0.05 O _3-δ , the conductivity of platinum-doped SrZr _0.9 Y _0.1 O _3-δ decreased significantly in a wet hydrogen atmosphere, whereas platinum-doped SrCe _0.95 Yb _0.05 O _3-δ showed almost no decrease in conductivity in the same atmosphere. The different responses of the two materials to the change in gas atmosphere are discussed in relation to the precipitation of platinum nanoparticles.