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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Surface Segregation in Chromium-Doped Nanocrystalline Tin Dioxide Pigments

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Author(s):
Castro, Ricardo H. R. [1, 2] ; Rufner, Jorgen [1] ; Hidalgo, Pilar [3] ; Gouvea, Douglas [4] ; Coaquira, Jose A. H. [5] ; van Benthem, Klaus [1, 2]
Total Authors: 6
Affiliation:
[1] Univ Calif Davis, Chem Engn & Mat Sci Dept, Davis, CA 95616 - USA
[2] Univ Calif Davis, NEAT ORU, Davis, CA 95616 - USA
[3] Univ Brasilia, Gama Coll & Energy Engn, BR-70910900 Brasilia, DF - Brazil
[4] Univ Sao Paulo, Dept Met & Mat Engn, BR-05508900 Sao Paulo - Brazil
[5] Univ Brasilia, Inst Fis, Nucl Fis Aplicada, BR-70910900 Brasilia, DF - Brazil
Total Affiliations: 5
Document type: Journal article
Source: Journal of the American Ceramic Society; v. 95, n. 1, p. 170-176, JAN 2012.
Web of Science Citations: 8
Abstract

Surface properties play an important role in understanding and controlling nanocrystalline materials. The accumulation of dopants on the surface, caused by surface segregation, can therefore significantly affect nanomaterials properties at low doping levels, offering a way to intentionally control nanoparticles features. In this work, we studied the distribution of chromium ions in SnO2 nanoparticles prepared by a liquid precursor route at moderate temperatures (500 degrees C). The powders were characterized by infrared spectroscopy, X-ray diffraction, (scanning) transmission electron microscopy, Electron Energy Loss Spectroscopy, and Mossbauer spectroscopy. We showed that this synthesis method induces a limited solid solution of chromium into SnO2 and a segregation of chromium to the surface. The s-electron density and symmetry of Sn located on the surface were significantly affected by the doping, while Sn located in the bulk remained unchanged. Chromium ions located on the surface and in the bulk showed distinct oxidation states, giving rise to the intense violet color of the nanoparticles suitable for pigment application. (AU)

FAPESP's process: 05/53241-9 - Study of intergranular phenomena in ceramic materials
Grantee:Reginaldo Muccillo
Support Opportunities: Research Projects - Thematic Grants