Poster NanoSpain2008 14-18 April, 2008 Braga-Portugal MODIFIED ELECTRODE BASED ON ZEOLITE-ENCAPSULATED Cr(III) COMPLEX Sara Gonçalves 1 , Hugo Figueiredo 2 , Bruna Silva 2 , Teresa Tavares 2 , Pier Parpot 1 , Isabel C. Neves 1 , António M. Fonseca 1 , Anna E. Lewandowska 3 , Miguel A. Bañares 3 1 Departamento de Química, Universidade do Minho, Campus de Gualtar, 4170-057 Braga, Portugal - Email:ineves@quimica.uminho.pt 2 IBB − Instituto de Biotecnologia e Bioengenharia, Centro de Engenharia Biológica, Universidade do Minho, Campus de Gualtar, 4710-057, Braga, Portugal - Email:ttavares@deb.uminho.pt 3 Instituto de Catálisis y Petroleoquímica, Instituto de Catálisis y Petroleoquímca, CSIC Universidad Autónoma de Madrid, E-28049-Madrid, Spain – Email: banares@icp.csic.es Zeolites are very important in materials science for the development of functional materials as well as in nanotechnology and these solids are very attractive in heterogeneous catalysis [1, 2]. For these applications, zeolites provide a rigid structure in which some active compounds can be included. In addition to the space constraints imposed by the zeolite, the negative charge of the zeolite framework and the distribution of the positive charges of the cations can lead to specific interactions with the zeolite framework which in turn induce structural and functional modifications as compared to solution activities [2]. The first syntheses of encapsulated complexes within zeolites generated much interest due to effects of site isolation and steric confinement on the physical properties and chemical reactivity of the molecules trapped within supercages of the crystalline microporous zeolite lattice [3]. Zeolite-encapsulated transition metal complexes are generally characterized by spectroscopic techniques and elemental analyses [4]. This work reports the studies of the electrochemical behaviour of Cr(III)-PAN complexes encapsulated in NaY zeolite. The redox properties of these zeolite-encapsulated complexes were investigated by cyclic voltammetry with a new method for the preparation of carbon toray-zeolite-modified electrode. The synthesis of Cr(III) complexes encapsulated in supercages of Y zeolite was carried out by free diffusion of the PAN (1-(2-pyridylazo)-2-naphtol) ligand (Figure 1) through the zeolite pores exchanged with the Cr(III) metal ion, obtained by the previous use of the biosorption process [5]. The resulting materials were characterized via surface analysis (SEM, XRD), chemical analysis, spectroscopic methods (FTIR and Raman) and cyclic voltammetry in aqueous medium with zeolite-modified electrodes. Figure 1 – 1-(2-pyridylazo)-2-naphtol (PAN) ligand Zeolite-encapsulated Cr(III)-PAN complex was deposited on carbon Toray (CT) in order to determine the electroreactivity by cyclic voltammetry. The cyclic voltammetry studies obtained with a new method for the preparation of zeolite-modified electrodes shows