Poster TNT2004 September 13-17, 2004 Segovia-Spain SILVER MONODISPERSED NANOPARTICLES SUPPORTED ON AND α−, η− AND δ − ALUMINA A. Esteban-Cubillo a , C. Díaz b , A. Fernández b , L. A. Díaz b* , C. Pecharromán a , J. L. Menéndez, R. Torrecillas b , J. S. Moya a . a Instituto de Ciencia de Materiales de Madrid (ICMM)-CSIC, Cantoblanco 28049 Madrid, Spain. b Instituto Nacional del Carbón (INCAR)-CSIC, Francisco Pintado Fe nº 26, 33011 Oviedo, Spain. *E-mail: rtorre@incar.csic.es The nanoscience and nanotechnology are two disciplines, evolving from an experimental state to the industrial production. However, up to now, the preparation of large quantities of nanostructured materials containing small and monodisperse particles is becoming one of the bottlenecks that hinders the development of commercial devices. In that sense, many references can be found in the literature describing nanoparticle preparation methods which they only remain monodispersed in liquid suspensions [1,2,3] (colloids) or embedded in rigid matrices [4,5]. Moreover, it is quite common, that nanoparticles, due to their large surface energy, induce aggregation processes, specially when they appear as single phase, for example, after drying a colloidal suspension. In the case that the monodisperse character of the nanoparticles is a crucial characteristic for the application, as it is the case of optical applications, colloidal methods cannot be employed straightforward. In fact, nanoparticles must be isolated, coated [1] or “frozen” in the colloid, before characterized or measured. In this work, precursors of silver monodispersed nanopaticles supported on different alumina phases (α −, η− and δ − Al 2 O 3 ) have been obtained by a colloidal processing route. Once the suspensions were dried and reduced, silver nanoparticles on the different alumina surfaces were obtained. Silver particle size varies between 100 and <5 nm as a function of the alumina phase. On the basis of HRTEM studies a mechanism of nucleation and growth of silver nanoparticles according to the nature of alumina surface have been proposed. The optical spectra of the samples were measured by diffuse reflectance from 300 to 750nm, revealing the presence of silver surface plasmons (figure 1), which supplies information about dispersion of nanoparticles into alumina matrices.