Stochastic electrochemistry for catalysis and analysis of carboneous bio-electrodes.

Description du projet

Améliorer le transfert des électrons dans les piles à combustible enzymatiques

Les piles à combustible à base de biocarburants enzymatiques constituent le parfait exemple d’une technologie de production de l’électricité en plein essor, qu’on appelle systèmes bioélectrochimiques (BES). L’amélioration du transfert d’électrons entre les électrodes et les enzymes qui se développent autour de celles-ci est l’un des défis à relever pour permettre la commercialisation des BES. Le projet STOCHELEC, financé par l’UE, s’y est attelé en synthétisant des électrodes à base de nanopoints de carbone; de telles nanostructures peuvent être élaborées de manière à correspondre aux niveaux d’énergie des enzymes redox actives et à améliorer leur stabilité ainsi que leur efficacité. L’amélioration du couplage électronique entre la surface de l’électrode et les catalyseurs enzymatiques permettra d’augmenter la production d’électricité.

Objectif

Bio-electrochemical sciences are essential for the development of biosensor and biofuels cells. The precise nano-structuration of conductive materials with electro-active enzymes allows the reversible transduction of electrical energy to chemical energy via direct electron transfer (DET). The operational stability of bio-electrocatalytic systems is limited by the constant and strong electrical field building-up at the interface. The electrode polarisation generates a strong and static electrical field rigidifying the interfacial electronic double layer, often preventing free enzymes’ dynamics and leading to an enzymes’ loss of activity due to the destruction of their active 3D structure. Customized electrical polarisation patterns have the potential to enhance both electro-enzyme stability and efficiency. Biological electronic transfers processes being non-linear, it is expected that electrical stochastic signal excitation can greatly influence the electron transfer process at a bio-electrode.

This proposal focusses on gaining new knowledge about the electronic stochastic and unambiguous stimulation of bio-electrodes for catalytic and analytical purposes. The first objective is to synthesize nanostructured carbon nano-dots (C-dots) electrodes for the immobilisation of redox enzymes. C-dots possess a so-called trap-state; an energetic level that can be engineered to match biological redox cofactor potentials and thus enhance electronic coupling between the electrode and redox active enzymes. The second aim is to investigate pulsed and alternative current polarisation for enhancing bio-electrocatalysts efficiency and electro enzymes’ stability with non-ambiguous electrical waveform. The third aim of this proposal is to develop a novel electro-analytical technique relying on the Fourier transform analysis of chronoamperometry signals stimulated by a stochastic signal polarisation of bio-electrodes (FTSC).