Oxidation Pathways in Bicomponent Ultrathin Iron Oxide Films

被引：41

作者：

Monti, M. ^{[1
]}

Santos, B. ^{[1
]}

Mascaraque, A. ^{[3
,4
]}

Rodriguez de la Fuente, O. ^{[3
,4
]}

Nino, M. A. ^{[2
]}

Mentes, T. O. ^{[2
]}

Locatelli, A. ^{[2
]}

McCarty, K. F. ^{[5
]}

Marco, J. F. ^{[1
]}

de la Figuera, J. ^{[1
]}

机构：

[1] CSIC, Inst Quim Fis Rocasolano, Madrid 28006, Spain

[2] Elettra Sincrotrone SCpA, I-34149 Trieste, Italy

[3] Univ Complutense Madrid, E-28040 Madrid, Spain

[4] UCM, Unidad Asociada IQFR CSIC, Madrid 28040, Spain

[5] Sandia Natl Labs, Livermore, CA 94550 USA

来源：

JOURNAL OF PHYSICAL CHEMISTRY C | 2012年 / 116卷 / 21期

关键词：

X-RAY-ABSORPTION; BAND-STRUCTURE; MAGNETITE; GROWTH; GAMMA-FE2O3; OXYGEN; NANOPARTICLES; MECHANISMS; SPELEEM;

D O I：

10.1021/jp300702d

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：

The reactive growth of ultrathin Fe oxide films on Ru(0001) has been studied and characterized using low-energy electron microscopy, diffraction, and laterally resolved spectroscopies. Under exposure to molecular oxygen at 900 K, we observed the growth of a bicomponent film composed of micrometer-sized flat triangular Fe3O4 (magnetite) islands on a FeO (wustite) wetting layer. Subsequent oxidation using NO2 at 600 K resulted in the chemical transformation of the initially grown film to a Fe2O3 composition but still in bicomponent form. The triangular magnetite islands evolve to gamma-Fe2O3 (maghemite), and the surrounding layer is converted to alpha-Fe2O3 (hematite). The evolution of both members of the bicomponent iron oxide films, wustite to hematite and magnetite to maghemite, can be understood by considering that both are topotactic transformations occurring by the diffusion of iron in octahedral sites to react with oxygen on the film's surface.

引用

页码：11539 / 11547

页数：9