Synthesis, characterization and electroanalytical application of a new SiO2/SnO2 carbon ceramic electrode

A new SiO₂/SnO₂ carbon ceramic composite was prepared by the sol-gel method, and its potential application in electrochemistry as a novel electrode material has been studied. The prepared xerogel was structurally and electrochemically characterized by scanning electron microscopy coupled to energy dispersive spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction and cyclic voltammetry. The composite was pressed in a rigid disk-shape and used as a conductive substrate to immobilize a water-soluble organic-inorganic hybrid polymer, 3-n-propyl-4-picolinium chloride silsesquioxane. The oxidation of nitrite was studied on this polymer film coated electrode in aqueous solution using cyclic voltammetry and differential pulse voltammetry. This modified electrode exhibited a better defined voltammetric peak shifted negatively about 60 mV. The linear detection limit found for nitrite was from 1.3 × 10⁻⁵ to 1.3 × 10⁻³ mol l⁻¹ and the detection limit was 3.3 × 10⁻⁶ mol l⁻¹.