Loading channels of SiO2 mesoporous matrices with Fe oxides

N. A. FELLENZ; L.A. CANO,; J. F. BENGOA; I. DE SOUZA AZEBEDO; S.G. MARCHETTI; R.C.MERCADER

Peru

Conferencia; Latin American Conferece on the application of Mösbauer effect-LACAME 2010; 2010

The applications of regular arrays of nanowires and nanotubes have stimulated lately a large number of studies. Some time ago we set about preparing these solids, starting with the embedding of hematite nanoparticles into the regular array of mesoporous matrices [1]. More recently, we have investigated different conditions of preparation to enhance some especial properties of the solids [2]. We found most attractive the regular array of pores of MCM-41 and SBA-15 matrices. The first one has a size and distance of its channels (at least an order of magnitude smaller than similar systems found in the literature) that, among other applications, opens up possibilities for high density storage devices. On the other hand, SBA-15 as support for Fe-catalysts, exhibits higher stability and larger pores toward synthesizing larger molecules. Because of their magnetic properties, magnetite or maghemite-loaded solids display more promising properties than hematite. In this presentation, we describe the difficulties and advances of our recent alternative experiments to induce the structural transformations that lead from hematite embedded nanowires to maghemite and magnetite ones. In addition, we discuss the stability issue of a solid made up of magnetite nanowires embedded in a matrix of MCM-41 in atmospheric conditions, and the prospects and possible applications of new matrices currently under investigation in our laboratory. [1] M.V.Cagnoli, et al., American Institute of Physics Conference Proceedings 765 (2005) 13 [2] L.A.Cano et al., Hyperfine Interact. (in press) Online First DOI 10.1007/s10751-009-0106-6