EXAFS Study of Dopant Ions with Different Charges in Nanocrystalline Anatase: Evidence for Space-Charge Segregation of Acceptor Ions

被引：8

作者：

Knauth, Philippe ^{[1
]}

Chadwick, Alan V. ^{[2
]}

Lippens, Pierre E. ^{[3
]}

Auer, Gerhard ^{[4
]}

机构：

[1] Univ Aix Marseille 1, CNRS, UMR 6264, Ctr St Jerome,Lab Chim Provence, F-13397 Marseille 20, France

[2] Univ Kent, Sch Phys Sci, Funct Mat Grp, Canterbury CT2 7NR, Kent, England

[3] Univ Montpellier 2, CNRS, UMR 5253, Inst Charles Gerhardt, F-34095 Montpellier 5, France

[4] TRONOX GmbH, Krefeld, Germany

来源：

CHEMPHYSCHEM | 2009年 / 10卷 / 08期

关键词：

anatase; cations; density functional calculations; doping; EXAFS spectroscopy; TITANIUM-DIOXIDE; ELECTRICAL-PROPERTIES; GRAIN-BOUNDARIES; DEFECT CHEMISTRY; TIO2; MODEL; OXIDE; SIZE; MICROSTRUCTURE; NANOTUBES;

D O I：

10.1002/cphc.200800806

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：

A series of dopants, including acceptor ions (Zn2+, Y3+), isovalent ions (Zr4+, Sn4+) as well as a donor ion, (Nb5+), were studied by EXAFS spectroscopy in nanocrystalline TiO2 anatase powders and nanoceramics. Similar results were found for nanocrystalline powders and nanocrystalline ceramics, made by hot-pressing the powders. Boundary segregation was observed for the acceptor ions yttrium and zinc, whereas tin, zirconium and niobium ions were placed on substitutional bulk sites and did not segregate, whatever their concentration. These results can be interpreted based on defect thermodynamics, in the framework of a space charge segregation model with positive boundary core, due to excess oxide ion vacancies, and negative space charge regions, where ionized acceptors are segregated.

引用

页码：1238 / 1246

页数：9

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