Table of Contents
International Journal of Spectroscopy
Volume 2011, Article ID 458089, 8 pages
Research Article

In Situ IR Characterization of CO Interacting with Rh Nanoparticles Obtained by Calcination and Reduction of Hydrotalcite-Type Precursors

1Dipartimento di Chimica Industriale e dei Materiali, Alma Mater Studiorum-Università di Bologna, V.le Risorgimento 4, 40136 Bologna, Italy
2Air Liquide, Centre de Recherche Claude Delorme1, Chemin de la Porte des Loges, BP 126, Les Loges-en-Josas, 78354 Jouy-en-Josas Cedex, France
3Dipartimento di Scienza dei Materiali e Ingegneria Chimica, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy
4CpR-INSTM for Materials with Controlled Porosity, Via Giusti 9, 50121 Firenze, Italy

Received 3 May 2011; Accepted 21 June 2011

Academic Editor: Sergio Armenta Estrela

Copyright © 2011 F. Basile et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Supported Rh nanoparticles obtained by reduction in hydrogen of severely calcined Rh/Mg/Al hydrotalcite-type (HT) phases have been characterized by FT-IR spectroscopy of adsorbed CO [both at room temperature (r.t.) and nominal liquid nitrogen temperature] and Transmission Electron Microscopy (TEM). The effect of reducing temperature has been investigated, showing that Rh crystal size increases from 1.4 nm to 1.8 nm when the reduction temperature increases from 750°C to 950°C. The crystal growth favours the formation of bridged CO species and linear monocarbonyl species with respect to gem-dicarbonyl species; when CO adsorbs at r.t., CO disproportionation occurs on Rh and it accompanies the formation of (CO)2. The role of interlayer anions in the HT precursors to affect the properties of the final materials has been also investigated considering samples prepared from silicate-instead of carbonate-containing precursors. In this case, formation of (CO)2 and CO disproportionation do not occur, and this evidence is discussed in terms of support effect.