A New Strategy for Immobilization of Electroactive Species on the Surface of Solid Electrode

This letter reports on a new method for immobilization of electroactive species on a solid electrode surface based on the composite film of naphthol green B (NGB) and Co-Al layered double hydroxides (LDHs). After the oxidation potential of Co(III)/(II) couple was dramatically enhanced by NGB, the functionalized LDHs exhibited a remarkable electrocatalytic activity toward the oxidation of hydrazine in a weak acidic medium. The amperometric response to hydrazine showed a linear range of 0.17 mu M-400 mM, with the calculated detection limit of 0.1 mu M at a signal-to-noise ratio of three and the sensitivity of the amperometric hydrazine sensor was found to be 35.26 mu A mu M-1. The modified electrode displayed an acceptable reproducibility and good stability. The new strategy is expected to have wide applications for changing of the potential of redox couple in metal oxides, hydroxides, double hydroxides, and so on.