Structural and electrochemical characterization of a cobalt phthalocyanine bulk-modified SiO2/SnO2 carbon ceramic electrode

A cobalt phthalocyanine bulk-modified carbon ceramic composite has been prepared by using sol-gel processing, and characterized by BET surface area, X-ray photoelectron spectroscopy, scanning electron microscopy and atomic force microscopy. A water-soluble 3-n-propylpyridinium chloride silsesquioxane (SiPyCl), an ion exchanger polymer, was employed to attach cobalt(II) tetrasulfophthalocyanine (CoTsPc) and prevent its leakage, as well as, to ensure adequate dispersion in the sol-gel network. The modified electrode built in a rigid disk-format displayed good electrocatalytic behavior towards the oxidation of oxalic acid at 0.84 V (SCE), as evidenced by the enhancement of the anodic current peak intensity when the concentration of oxalic acid was increased. A linear response was found in the range of 1.6 × 10⁻⁵ to 1.5 × 10⁻³ mol l⁻¹ with a detection limit of 7.1 × 10⁻⁶ mol l⁻¹.