DIAMOND-LIKE CARBON ELECTRODES - THE IMPEDANCE SPECTROSCOPY AND KINETICS OF REDOX REACTIONS

The impedance spectra and the oxidation and reduction voltammetric cur ves in solutions of quinone and hydroquinone in 0.5 M H2SO4 are measur ed for amorphous diamondlike carbon (a-C : H) electrodes deposited ont o glassy carbon substrates by the magnetron sputtering or ion source t echniques. The electrode's equivalent circuit includes a constant-phas e element. Only relatively narrow-bandgap films possess an inherent el ectrochemical activity. The wide-bandgap a-C : H becomes electrochemic ally active upon introducing a Pt admixture (approximately 10%) in the course of the film growth. The Pt-doped a-C : H is similar, in its ki netic characteristics, to the boron-doped polycrystalline diamond.