Nanocomposite electrodes made of carbon nanofibers and black wax. Anodic stripping voltammetry of zinc and lead

Nanocomposite electrodes offer exciting new possibilities in electroanalyti cal chemistry. In this preliminary study, nanocomposite electrodes made of carbon nanofibers and black wax were characterized and investigated as nove l substrates for metal deposition and stripping processes. Carbon nanofiber s were grown from ethylene-hydrogen gas mixtures over Fe-Ni-Cu (85:10:5) na noparticle catalysts at 600 degreesC and then embedded in Apiezon black wax under vacuum at 140 degreesC. The resulting nanocomposite electrodes showe d (i) good conductivity, (ii) a wide potential window in aqueous solutions, (iii) low background currents, (iv) near steady state voltammetric respons es with substantial Faradaic currents and (v) sharply peaked fast scan meta l stripping responses. Zinc is a notoriously difficult metal to determine i n aqueous solutions, because its deposition and stripping are accompanied b y hydrogen evolution at extreme negative potentials. It therefore provided a challenging test for our new nanocomposite electrode. Although numerous c omplications associated with the hydrogen evolution process could not be el iminated, remarkably clear voltammograms could be obtained even at scan rat es of 40 V s(-1).