The properties and electrocatalytic activity were studied of composite carbon-supported materials based on heterocyclic polymer and nickel, in particular carbon / polyaniline / nickel, carbon/ polypyrrole / nickel, carbon / poly(3-methylthiophene) / nickel, as well as their precursors, carbon / polyaniline, carbon / polypyrrole, and carbon/ poly(3-methylthiophene). The materials were characterized by means of thermogravimetric analysis (TGA), scanning electron microscopy (SEM), EDAX, and electro-chemical methods, such as cyclic voltammetry and linear voltammetry using RDE. SEM show porous materials, with a particle size of around 0.3 mu m. It was found that in nickel-modified catalysts between 5 and 6 wt % of nickel is obtained. TGA and FTIR show that the modification with nickel alters the polymer bonds. Curves from cyclic voltammetry show cathodic peaks corresponding to the oxygen reduction reaction (ORR) in all materials, occurring at relatively low potentials. Based on the potential range for ORR as well as kinetic parameters obtained from linear voltammetry using RDE, it was concluded that C-Ppy-Ni shows the best performance for ORR in acidic medium. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 112: 2959-2967, 2009