Département de chimie moléculaire

The electrochem. properties of natural or synthetic ferruginous clays, nontronite, montmorillonite and saponite, were studied by cyclic voltammetry and impedancemetry. Clay modified electrodes were then tested for the redn. of H2O2 under different conditions: in acidic medium without redox mediator, in phosphate buffer solns. (pH 7 or 8) with a redox cation (Me viologen, MV2+) or a biomol. (Hb) absorbed within the clay coating. In all cases, the presence of Fe species in the octahedral lattice of the clays enhanced the electrocatalytic redn. currents of H2O2. The sensitivities of H2O2 calibration curves were 0.23, 54 and 132 mA/M cm2 for Nont, MV2+-Nont and Hb-Nont modified electrodes, resp. [on SciFinder(R)]