Preparation, characterization and redox reactivity of glassy carbon electrode modified with organometallic complex of nickel

Abstract

The organometallic complex of nickel (S)-[O-[(N-benzylpropyl)amino](phenyl)methyleneiminoacetate(2-)-N,N′,N″-nickel(II), labeled Ni-(S)BPB-Gly, irreversibly adsorbed on a glassy carbon electrode, displays electrocatalytic activity toward the oxidation of methanol in alkaline solution. Electrochemical properties of the resulting material deposited as a redox film have been investigated by cyclic voltammetry. Using Laviron's theory, the electron-transfer rate constant and the transfer coefficient were determined to be k=1.94s−1 and α=0.5, respectively, for a poly-Ni-(S)BPB-Gly film (ΓNi=9×10−10molcm−2) on a glassy carbon electrode in 0.1M sodium hydroxide solution. Chronoamperometric studies were also used to determine the catalytic rate constant for the catalytic reaction of the tested modifier with methanol (kcat=0.33×105cm3mol−1s−1). The dependence of the methanol oxidation current on the alcohol concentration and on the number of redox centers Ni(II)/Ni(III) is discussed. From the fact that the oxidation current increases with an increase of film thickness it is evident that the electrocatalytic reaction occurs inside the tested film. The system examined is a typical example of a redox layer with 3D properties. The modified electrode for methanol oxidation is characterized by simple preparation, good stability and good reproducibility.