The preparation and characterization of a surface renewable carbon-ceramic electrode, SiO2/SnO2/C-graphite/(SiPy+)(4)CoPcTs-4, is reported. Cobalt(II) tetrasulfonated plithalocyanine (CoPcTs-4) absorbed on a 3-n-propylpyridinium chloride silsesquioxane polymer was dispersed in a stannic-silica C-graphite sol-gel matrix. The performance of SiO2/SnO2/C-graphite/(SiPy+)(4)CoPcTs-4 as electrode material was investigated by cyclic voltammetry in the electrocatalytic oxidation of oxalic acid and nitrite. The modified carbon-ceramic material was characterized by X-ray fluorescence spectroscopy, BET specific surface area, thermogravimetric analysis, X-ray photoelectron spectroscopy, and scanning electron microscopy. (c) 2008 Elsevier B.V. All rights reserved.61714552