A Gas-phase Electrochemical Reactor for Carbon Dioxide Reduction back to Liquid Fuels

We discussed here on a novel approach to recycle CO2 back to liquid fuels by using nanostructured carbon-based materials (doped with suitable metal nanoparticles) as electrocatalysts. This approach is based on the development of a new photo-electrocatalytic (PEC) reactor, working in gas phase, which is quite different from the conventional reactors that operate typically in aqueous slurry and/or in batch. Gas phase operation, under solvent-less conditions, has many advantages (easy recovery of the products, no problems of CO2 solubility, etc.) with respect to liquid phase. The reaction mechanism is also quite different and longer chains of products can be obtained. In particular we investigated the competition of the side reaction of H2 formation by water electrolysis (which is unavoidable in such kinds of systems) with the CO2 reduction process. The understanding of this competitive reaction is very significant in order to maximize the process performances. Moreover the capability to develop advanced nanostructured electrodes, by modulating their properties during the synthesis, allowed to improve the efficiency of the CO2 reduction process, enhancing the productivity and tuning the selectivity towards higher chain hydrocarbons and other chemicals. The CO2 reduction to liquid fuels by solar energy represents an attractive solution which may contribute to the alternative use of clean and renewable sources to cope with the depletion of fossil fuels. The target is to develop a sort of “artificial leaf” which may collect the solar energy as the nature does, by capturing directly CO2 and converting it back to fuels.