Electrochemical properties of nanodiamond powder electrodes

Detonation-synthesized nanocrystalline diamond is a novel carbon material. Its increased electrical conductivity, due to the features of giant specific surface area and large numbers of surface defects as well as the cluster structure, makes it possible to be used as an electrode material. Nanodiamond powder electrodes were fabricated and the electrochemistry was investigated by cyclic voltammetry and AC impedance measurement. The results show that nanodiamond powder electrode is electrochemically stable in KCl electrolytes over a wide potential range (? 1.2–2.0 V). The electrode reaction is quasi-reversible in 0.1 M KCl containing the ferricyanide–ferrocyanide redox couple. The electrode reaction rate constant k is estimated to be 2.87 × 10^? 3 cm/s. The peak current increases linearly with the rising of the concentration of Fe(CN)₆]^3?/4?. The AC impedance spectra have been analyzed and an equivalent circuit proposed.