Oxidation catalysts based on metal nanoparticles supported on mesoporous silica

Abstract

Oxidation processes are extremely important on fine chemicals synthesis and of intermediary products; in particular, primary alcohols oxidation to aldehydes is of fundamental importance in laboratory and industrial procedures. The use of heterogeneous catalysts supported with metal nanoparticles has been proposed as an alternative to stoichometric oxidations, which involve the use of toxic reactants and are major sources of waste. The choice of the catalyst support, as well as the metal species, are of great importance and greatly influence the catalytic activity. The use of mesoporous silica as heterogeneous catalysts support is particularly interesting, mainly for the possibility of confining the nanoparticles, which lowers metal leaching and limits the nanoparticles growth. Although there are reports about the use of catalysts based on mesoporous silica containing bimetallic nanoparticles in alcohols oxidation reactions, not much is known about the mechanism by which the reaction proceeds and what is the role of which of the metal species in the process. This project proposes the preparation of catalysts based on mesoporous silica supported with mono or bimetallic nanoparticles of Au, Ag, Pt or Pd for the application in the reaction of oxidation of benzyl alcohol. These materials will be characterized and their morphological characteristics will be correlated with their catalytic activity. A detailed comparison between groups of materials that relate with each other and with complementary information will be realized, in order to obtain evidence on the action of the catalytic species in the process of oxidation of the alcohol molecule. (AU)