An alternating, hafnium-O-phenylene hybrid copolymer was calcined under the reduced pressure at 400-700 degrees C to obtain black-colored materials. XRD and TEM analyses showed that the calcined materials were composed of carbon clusters with the diameters of 20 nm and hafnium oxide particles with the diameters of a few nm. ESR spectral examinations revealed that the calcined materials formed a stable cation radical on the carbon Clusters and exhibited an oxidation-reduction function. When Au particles were Supported on the material. an efficient oxidation-reduction function was found to appear. (C) 2008 Elsevier B.V. All rights reserved.