Résumé
First, I shall present our demonstrator plant for the production of hydrogen using a commercial vanadium redox battery (10 kW installed, 200kW in preparation). The process is based on the redox catalysis of protons by vanadium (II) outside the battery in an external circuit comprising a catalytic bed of Mo2C on ceramic. The physico-chemical principal of redox catalysis on metallic nanoparticles will be discussed.
Then, I shall present our "dream" project of batch water splitting using biphasic systems. The idea is to use two biphasic water/oil systems. In both systems, we place in the oil phase an electron D and an electron acceptor A. In system 1, we have a catalyst for proton reduction and in system 2 one catalyst for water oxidation. Under day light, system 1 produces hydrogen and the donor is oxidised and system 2 produces oxygen and the acceptor is reduced. At night, the two oil phases are mixed to reset the redox couples. This membraneless approach provides a means to generate H2 and O2 separately.
Thirdly, I shall present our work on photo-ionic cells to convert solar energy and to generate electricity on demand. The concept is also based on a biphasic system. We place for example a cationic dye in water together with a redox quencher. Upon photo reaction, the neutral reduced dye is extracted to the organic phase. The two phases are then separated and the energy is then stored as redox energy. To recover this energy, we pass the two solutions in an electrochemical flow cell to generate electricity on demand.
Finally, I shall present our work on CO2 reduction using super critical CO2. First, I shall present the photoreduction of CO2 at the water/sc CO2 interface and then present our electrochemical investigations of CO2 reduction in scCO2-solvent mixtures using metal-organic catalysts.
