TY - JOUR
T1 - Nanoionics phenomenon in proton-conducting oxide
T2 - Effect of dispersion of nanosize platinum particles on electrical conduction properties
AU - Matsumoto, Hiroshige
AU - Furuya, Yoshihisa
AU - Okada, Sachio
AU - Tanji, Takayoshi
AU - Ishihara, Tatsumi
N1 - Funding Information:
This study was supported by a Grant-in-Aid for Scientific Research on Priority Areas “Nonoionics (No. 439)” by the Ministry of Education, Culture, Sports, Science and Technology, Japan.
PY - 2007/9
Y1 - 2007/9
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=36348951422&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=36348951422&partnerID=8YFLogxK
U2 - 10.1016/j.stam.2007.09.008
DO - 10.1016/j.stam.2007.09.008
M3 - Article
AN - SCOPUS:36348951422
VL - 8
SP - 531
EP - 535
JO - Science and Technology of Advanced Materials
JF - Science and Technology of Advanced Materials
SN - 1468-6996
IS - 6
ER -