Nanoionics phenomenon in proton-conducting oxide: Effect of dispersion of nanosize platinum particles on electrical conduction properties

Hiroshige Matsumoto, Yoshihisa Furuya, Sachio Okada, Takayoshi Tanji, Tatsumi Ishihara

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)

Abstract

High-temperature proton conductors are oxides in which low-valence cations are doped as electron acceptors; the incorporation of water molecules into the oxides results in the formation of protonic defects that act as charge carriers. Since the protons thus formed are in equilibrium with other electronic defects, electrons and holes, the oxides possibly have different proton-conduction properties at and near boundaries when they are in contact with another phase. In this paper, we present our recent experimental observation of a marked change in the electrical properties of a proton conductor upon the dispersal of fine platinum particles in the oxide. First, the material shows extremely low electrical conductivity in comparison with the original proton-conducting perovskite. Second, there was a threshold amount of platinum at which such a drop in conductivity occurred. A percolation model is employed to explain these experimental results; the fine platinum particles dispersed in the proton-conducting oxide wears highly resistive skin that is formed due to shifts in defect equilibriums, which prevents ionic/electronic conduction. The experiments suggest that the ion-conducting properties of oxides can be varied by introducing interfaces at a certain density; nanoionics is a key to yielding enhanced and/or controlled ionic conduction in solids.

Original languageEnglish
Pages (from-to)531-535
Number of pages5
JournalScience and Technology of Advanced Materials
Volume8
Issue number6
DOIs
Publication statusPublished - Sep 1 2007

All Science Journal Classification (ASJC) codes

  • Materials Science(all)

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