Indophenol and o-quinone derivaties immobilized on zirconium phosphate for NADH electro-oxidation
Forskningsoutput: Tidskriftsbidrag › Artikel i vetenskaplig tidskrift
The electrocatalytic properties for NADH oxidation of five organic dyes, two indophenol derivatives (2,6-dichlorophenolindophenol and indophenol) and three o-quinone derivatives (phenanthrenequinone, pyrroloquinoline-quinone, and 1,2-naphthoquinone) were compared when adsorbed on zirconium phosphate entrapped in carbon paste. The electrochemical behavior of the immobilized dyes was investigated with cyclic voltammetry, performed in different aqueous buffers, at different potential scan rates and pH values. The electrocatalytic efficiency for NADH oxidation was evaluated from cyclic voltammetry, and the second order electrocatalytic rate constant was calculated from rotating disk electrode experiments, at various concentrations of NADH and pH values. These studies indicate that the mechanism of such electro-oxidation proceeds via the formation of an intermediate complex. A positive effect with the addition of Ca2+ cations to the solution was observed and the reaction rate for NADH oxidation increased. The highest second order rate constant was obtained for 2,6-dichlorophenolindophenol and found to be 4.6 × 106 M-1 s-1.