ELECTROCATALYTIC ACTIVITY FOR O2 REDUCTION OF UNSUBSTITUTED AND PERCHLORINATED IRON PHTHALOCYANINES ADSORBED ON AMINO-TERMINATED MULTIWALLED CARBON NANOTUBES DEPOSITED ON GLASSY CARBON ELECTRODES

Abstract

ABSTRACT Amino-functionalized multiwalled carbon nanotubes (MWCNT-NH 2 ) were modifiedwith Fe phthalocyanine (FePc) and perchlorinated Fe phthalocyanine (16(Cl)FePc) and deposited on glassy carbon electrodes (GCE). The electrocatalytic activity of these hybrid electrodes was examined for the reduction of molecular oxygen in alkaline media (0.2 M NaOH) using stationary and rotating disk electrodes. Electrodes containing 16(Cl)FePc are more active than those containing FePc. Electrodes containing CNTs are more active than electrodes without CNTs but the higher activity can be attributed to a greater real surface area, compared CGEs and not necessarily to a catalytic effect. Keywords: Amino-terminated carbon nanotubes, Fe phthalocyanines, O2 reduction, catalytic activity. INTRODUCTION MN4 macrocyclic metal complexes are well known as catalyst for many electrochemical reactions, specially the reduction of O 2 and their activity is directly related 6,7to their redox properties . On the other hand, carbon nanotubes (CNTs) 8are interesting support materials for the modificationof substrates. CNTs increase the area of the electrodes and when this is combined with MN4 macrocyclic complexes 7,9-13substantial improvements in the reactivityare observed. The specificchemistry of the surface of CNTs can be tailored by changing the nature of surface groups that can be created on their surface by appropriate chemical treatment, 8-13adapting them for a desired application . A non-chemical way of modificationof CNTs is by simple adsorption of macrocyclic complexes on the external walls of the CNTs where the molecules stick to them by π-π interactions. If carbon nanotubes are modifiedwith amino groups -NH