Octahedral and tetrahedral cobalt species in nanodimensional pores of mordenite zeolite as modified carbon paste electrode for determination of ascorbic acid

A new method is developed for the catalytic oxidation of ascorbic acid (AA) at zeolite-modified carbon paste electrode, doped with cobalt (II) (Co²⁺ MOR/ZME). Characterisation of Co²⁺-loaded mordenite zeolite has been carried out by diffuse reflectance spectroscopy (DRS), Fourier transform-infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). FTIR and DRS show octahedral and tetrahedral Co²⁺ species into mordenite channels. TEM pictures reveal the formation of cobalt phyllosilicate. Cobalt (II) exchanged in zeolite-type mordenite acts as a catalyst to oxidise AA. The modified electrode lowered the overpotential of the reaction by ~500~mV. The mechanism of electrochemical oxidation of AA using modified electrode was investigated by cyclic voltammetry (CV) study. Results of CV using this modified electrode show one well-resolved anodic wave for the oxidation of AA, which makes it possible for determination of compound.