Conductivity and hydration trends in disordered fluorite and pyrochlore oxides: A study on lanthanum cerate-zirconate based compounds

被引：31

作者：

Besikiotis, Vasileios ^{[1
]}

Ricote, Sandrine ^{[2
]}

Jensen, Molly Hjorth ^{[2
]}

Norby, Truls ^{[1
]}

Haugsrud, Reidar ^{[1
]}

机构：

[1] Univ Oslo, Dept Chem, FERMiO, NO-0349 Oslo, Norway

[2] Tech Univ Denmark, Dept Energy Convers & Storage, DK-4000 Roskilde, Denmark

来源：

SOLID STATE IONICS | 2012年 / 229卷

关键词：

Proton conductivity; Disorder; Pyrochlores; Fluorites; Isotope effect; TG-DSC; PROTON CONDUCTIVITY; TRANSPORT-PROPERTIES; ELECTROLYTE; DIFFUSION; STABILITY; DEFECTS; WATER;

D O I：

10.1016/j.ssi.2012.10.004

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

In the present contribution we discuss the influence of order/disorder on the concentration and mobility of ionic charge carriers in undoped and acceptor (calcium) doped fluorite and pyrochlore structured lanthanum cerate-zirconate solid solutions: (La1-yCay)(2)(Ce1-xZrx)(2)O7-delta (y = 0, 0.02, 0.10; x = 0, 0.50, 0.75). Characterization of the electrical conductivity as a function of temperature and oxygen partial pressure revealed contribution from electronic carriers in reducing atmosphere, but otherwise these materials are ionic conductors. Oxide ion conductivity dominates at high temperatures while protons become more dominating as charge carrier at temperatures below typically 500 degrees C under wet conditions. The hydration enthalpies were determined by simultaneous thermogravimetry and differential scanning calorimetry (TG-DSC). The contribution from ionic conductivity increases and the hydration enthalpy becomes more exothermic with higher cerium content, i.e. with more disordered materials. The proton conductivity decreases upon acceptor substitution of La3+ with Ca2+ which is attributed to trapping of the charge carriers by the effectively negative acceptor. (c) 2012 Elsevier B.V. All rights reserved.

引用

页码：26 / 32

页数：7