Sol–gel derived terbium hexacyanoferrate modified carbon ceramic electrode: Electrochemical behavior and its electrocatalytical oxidation of ascorbic acid

A new kind of modified electrode fabricated by mechanically attaching terbium hexacyanoferrate (TbHCF) samples to the surface of carbon ceramic electrodes (CCEs) derived from sol–gel technique was proposed. The resulting modified electrodes exhibit well-defined redox responses with the formal potential of +0.225 V (vs. SCE) at a scan rate of 20 mV s−1 in 0.5 M KCl (pH 7) solution. The voltammetric characteristics of the TbHCF-modified CCEs in the presence of different alkali metal cations (Li+, Na+, K+, Rb+ and Cs+) were investigated by voltammetry. The TbHCF-modified CCEs presented a good electrocatalytic activity toward the ascorbic acid (AA) and was used for amperometric detection of AA. The diffusion coefficient (D) of AA in solution and the catalytic rate constant (kcat) were also calculated by chronoamperometry experiment. In addition, the TbHCF-modified CCEs exhibited a distinct advantage of the ability for amperometric detection of AA in the presence of uric acid (UA) by controlling the applied potential at low value (0.25 V).