CONICET | Buscador de Institutos y Recursos Humanos

In the last decade the discussion about a replacement of classical fossil fuels as petrol, gas and coal has been getting more and more important. Not only a replacement of the fuels but also the efficiency of the combustion and the energy conversion are important aspects for the global ecology. For both of these problems the electrochemical combustion in fuel cells present a very promising way to reach these goals. That is because these kind of cells have very high efficiencies and use ecologically friendly fuels like hydrogen, methanol or glucose and in addition they are miniaturizable, mobile and continuously usable by refilling the fuel. But one problem of these systems represent the catalyst, usually noble metals or their alloys, that are expensive, non selective and very sensitive to poisoning. Therefore in the last years more and more groups use enzymes as catalysts instead of inorganic catalysts e.g. Pt/Ru. The mostly used enzymes are Glucose Oxidase (glucose oxidation), Bilirubidium Oxidase and Laccase (both for oxygen reduction) and the design of so called biofuel cells have been reported on several occasions [1-3]. In this presentation we report the preparation of Trametes togii (arg.) Laccase modified electrodes using the layer-by-layer self assembly technique (lbl) with Os-redox polymers as polycation with integrated redox mediator and the enzyme as polyanion. The main advantage of this approach over other methods [3-6] is that almost all important film properties (thickness, concentration of enzyme and mediator, permeability etc.) can be controlled by the choice of the number of layers and the deposition pH. The dependence of the catalytic current on the oxygen partial pressure, the pH during the lbl deposition and during the electrochemical measurement was studied. We also have studied the tolerance of these cathodes to methanol.