Efficient preparation of silver nanoparticles supported on hybrid films and their activity in the oxidation of styrene under microwave irradiation

Hybrid films containing different loadings of silver nanoparticles (0.5, 1 and 2.5 wt.%) have been prepared using a sol-gel method. Three types of materials were prepared in order to compare their properties: Ag nanoparticles (NPs) on hybrid film containing methyltrimethoxysilane (Ag-MeTMS), a similar hybrid material containing both MeTMS and 3-mercaptopropyltrimethoxysilane (MPTMS) as modifier (Ag-MeTMS/MPTMS) and finally a Ag-MeTMS film to which starch was added as modifier/reducing agent (Ag-MeTMS/starch). Characterized materials by TEM showed that, in general, Ag materials had a bimodal particle size distribution, with sizes of 7-8, 12-16 nm as well as some bigger agglomerates (on some of them) of 24-25 nm present at increasing silver loadings. The catalytic properties of the supported Ag NP were investigated in the oxidation of styrene. Ag-MeTMS/MPTMS materials were comparatively more active and selective than Ag-MeTMS or Ag-MeTMS/starch, regardless of the Ag content in the materials, providing high conversions and selectivities to styrene oxide. (C) 2009 Elsevier B.V. All rights reserved.