Electroless preparation and electrochemistry of nickel-pentacyanonitrosylferrate film modified aluminum electrode

The use of aluminum substrate as an electrode and the modification of its s urface by means of the thin film of nickel pentacyanonitrosylferrate (NiPCN F) was developed. The modification conditions of aluminum surface including the electroless deposition of metallic nickel on the electrode surface fro m NiCl2 + NH4Cl solution and chemical derivatization of deposited nickel to NiPCNF film in solution of 10 mM sodium pentacyanonitrosylferrate (PCNF) 0.5 M NaNO3 + 0.03 M HNO3 are described. The modified Al electrode prepare d under optimum conditions, shows a well-defined redox couple due to [(NiFe III/II)-Fe-II(CN)(5)NO](0/-1) system. The effect of pH and radius of the hy drated aikali-metal cation of supporting electrolyte on the electrochemical characteristics of the modified electrode were studied in detail. Diffusio n coefficients of aikali-metal cations in the film (D),transfer rate consta nt for electron (k(s)) and transfer coefficient (alpha) were calculated. Th e electrocatalytic activity of the modified electrode on the oxidation of h ydrogen peroxide and ascorbic acid was demonstrated as a typical example of applications.