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Surface Segregation in Chromium-Doped Nanocrystalline Tin Dioxide Pigments
Article first published online: 4 OCT 2011
© 2011 The American Ceramic Society
Journal of the American Ceramic Society
Volume 95, Issue 1, pages 170–176, January 2012
How to Cite
Castro, R. H. R., Rufner, J., Hidalgo, P., Gouvêa, D., Coaquira, J. A. H., van Benthem, K. (2012), Surface Segregation in Chromium-Doped Nanocrystalline Tin Dioxide Pigments. Journal of the American Ceramic Society, 95: 170–176. doi: 10.1111/j.1551-2916.2011.04868.x
- Issue published online: 3 JAN 2012
- Article first published online: 4 OCT 2011
- Manuscript Accepted: 27 AUG 2011
- Manuscript Received: 13 MAY 2011
- FAPESP. Grant Number: 05/53241-9
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°C). The powders were characterized by infrared spectroscopy, X-ray diffraction, (scanning) transmission electron microscopy, Electron Energy Loss Spectroscopy, and Mössbauer 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.