Design of Catalysts Based on Metal Nanoparticles Supported on Organofunctionalized Mesoporous Silicas

• Grant number: 11/13434-3
• Support type: Scholarships in Brazil - Doctorate
• Effective date (Start): December 01, 2011
• Effective date (End): October 31, 2013
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Inorganic Chemistry
• Principal researcher: Yoshitaka Gushikem
• Grantee: Natália Fattori
• Home Institution: Instituto de Química (IQ). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil

Abstract

The aim of the present project is the design of new catalysts based on metal nanoparticles supported on organfunctionalized mesoporous silicas. Two different substrates will be explored: the first one is constituted by a highly ordered and uniform porous framework, with parallel cylindrical pore channels packed in a hexagonal array (SBA-15). The second matrix is characterized by a disordered porous framework, with non-uniform size and shape, distributed and interconnected randomly throughout the porous structure (Disordered Mesoporous Silica, SMD).The two distinct substrates will be chemically modified with four different functional agents constituted of organic cations (R+Cl-) with ion exchange properties, derived from the molecules 4,4'-bipyridine, 4 metylpyridine, 1-metylimidazol and 1,4-diazabicyclo[2.2.2]octane (Dacbo).The modified matrices will be used as solid supports for the preparation and stabilization of metal nanoparticles (Au, Pt, Pd and metal alloys Au-Pt, Au-Pd e Pt-Pd). The ion exchange properties of the organic cations anchored on the silica surface enable the retention of noble metal anionic complexes (AuCl4-, PtCl62- and PdCl42-) confined in the porous structure. These anionic species will be converted into the corresponding metal nanoparticles by the reduction of the metallic ions with proper reducing agents. The effects of the matrices porous structure as well as the different functional agents in the stabilization, shape and size of the prepared nanoparticles will be studied in details. The catalytic performance of the materials prepared will be tested in the selective oxidation of different types of alcohols.