Electrochemical properties of Pr-doped Ce(Gd)O2-δ
Electrochemical properties of Pr-doped Ce(Gd)O2-δ
复制标题
DOI：
10.1016/s0167-577x(01)00469-4
复制
发表时间：
2002-03-01
影响因子：
3
通讯作者：
Marques, FMB
中科院分区：
文献类型：
--
作者：
Kharton, VV;Viskup, AP;Marques, FMB
在Ce0.80Gd0.20O2-delta的荧光型晶格中，用镨离子取代2%钆可使p型电子电导率提高2.5 ~ 4倍，而电子-空穴输运的活化能从145 ~ 125 kJ/mol降低。在空气中723 ~ 1073 K时，与ge0.80 gd0.18 pr0.002 -delta固体电解质接触的多孔Pt电极的极化电阻比ce0.80 gd0.20 -delta陶瓷电极的极化电阻低0.5 ~ 3倍。这种行为表明了铈基电解质表面在电化学过程中的积极作用，这归因于较大的p型电导率以及镨离子的高电催化活性。通过将氧化镨掺入Pt金属电极基体中，可以进一步降低极化电阻。ce0.80 gd0.18 pr0.022 - δ陶瓷的显微组织研究表明，Pr的掺杂增加了稀土掺杂物在晶界的偏析倾向；分离的富pr相可能对电化学活性有积极的影响。(C) 2002 Elsevier Science B.V.版权所有
Substitution of 2% gadolinium in the fluorite-type lattice of Ce0.80Gd0.20O2-delta with praseodymium cations was found to increase the p-type electronic conductivity by 2.5-4 times, whereas the activation energy for the electron-hole transport decreases from 145 to 125 kJ/mol. The polarization resistance of porous Pt electrodes in contact with Ge0.80Gd0.18Pr0.02O2-delta solid electrolyte, determined by impedance spectroscopy at 723-1073 K in air, is 0.5-3 times lower than that for Ce0.80Gd0.20O2-delta ceramics. This behavior, indicating an active role of the surface of the ceria-based electrolytes in electrochemical processes, was attributed to the larger p-type conductivity as well as to the high electrocatalytic activity of praseodymium cations, Further decrease in polarization resistance can be achieved by incorporation of praseodymium oxide into the Pt metal electrode matrix. Microstructural studies of Ce0.80Gd0.18Pr0.02O2-delta ceramics showed that Pr doping increases the tendency for segregation of rare-earth dopants at the grain boundaries; the segregated Pr-enriched phase may have a positive effect on electrochemical activity. (C) 2002 Elsevier Science B.V. All rights reserved.