Catalytic and electrocatalytic properties of intrazeolitically prepared iron phthalocyanine

Iron-phthalocyanine (FePc) has been successfully synthesised inside the por es of the NaY zeolite as evidenced by various physicochemical characterisat ion methods such as scanning electron microscopy (SEM), X-ray diffraction ( XRD), electron spin resonance spectroscopy (ESR), ultraviolet spectroscopy (UV), cyclic voltammetry (CV) and thermal methods of analysis. XRD analysis indicates the formation of FePc molecules inside the supercages. SEM pictu res show that the original microporous nature of NaY is not affected by enc apsulation of FePc. ESR spectrum shows two peaks with g values of 1.977 and 4.030 indicating the partial oxidation of FePc in the cavity, while IR spe ctra suggest that the molecule can undergo a saddle deformation inside the zeolite matrix. In UV-Vis spectrum, the Q band of the FePc molecule is shif ted from 656 nm to 686 nm, although the soret band is less affected. Therma l analysis indicates that these molecules have enhanced thermal stability i nside the zeolite cavities. Cyclic voltammetric studies show that the elect rochemical behaviour of pure FePc is not much affected by the encapsulation . The encapsulated FePc molecules are found to catalyse the hydrocarbon oxi dation reactions. In addition, modified electrodes prepared with this mater ial indicate good electrocatalytic effects as demonstrated by a 260 mV shif t in the peak potential for oxygen reduction in neutral medium. Considerabl e electrocatalytic behaviour is also observed for oxidation of hydrazine. ( C) 1999 Elsevier Science S.A. All rights reserved.