Nix–Fe(1−x)Fe(CN)6 hybrid thin films electrodeposited on glassy carbon: Effect of tuning of redox potentials on the electrocatalysis of hydrogen peroxide

The electrochemical deposition of mixed Nix–Fe(1−x)Fe(CN)6 thin films on a glassy carbon (GC) electrode surface were carried out by electro-deposition under continuous potential cycling condition for the first time. The redox potential of the low spin iron in the hybrid film was found to depend on the ratio of metal centres. The improvement in the electrocatalytic property of the nickel hexacyanoferrate film with incorporation of iron ions in the film towards the electrocatalysis of hydrogen peroxide was studied in electrolytes like KNO3 and NaNO3. The stability of hybrid film in Na+ containing supporting electrolytes was examined. Detection limit of H2O2 was about 1 μM as determined by amperometry with the sensitivity of 192 nA/μM. The chemically modified glassy carbon electrodes with NixFe(1−x)HCF hybrid films were characterized by cyclic voltammetry, impedance spectroscopy, energy dispersive X-ray analysis etc. These films may find extensive applications as redox mediators in biosensors which employ oxidase enzymes.

► Electrochemical formation of hybrids of FeHCF – NiHCF is reported in this work for the first time. ► Heteroatom in the lattice of a metal hexacyanoferrate film results in the opening of new electron transfer channel. ► Observation of the shift in redox potential (Tuning) as a function of the Ni2+% in the film is quiet new. ► The electrochemically prepared MHCF hybrids are shown to have improved stability in sodium containing electrolytes.