Fuel Generation by Hydrogenation of Carbon Dioxide via Plasma-Assisted Catalysis

A challenge in the scientific research for strategies using low-cost renewable energy is to design and develop heterogeneous/homogeneous catalysis processes converting waste CO2 into fuels in a circular economy regime. An experimental study aiming at reusing CO2 and implementing a validated laboratory technology based on a prototype methanation reactor producing carbon neutral methane through the chemical conversion of CO2 waste flue gases using renewable energies, is presented. Experimental determinations of methane yields have been carried out using CO2 either taken from commercial bottles or produced from fermentation of wine and vegetable exhausted materials. Furthermore, we have also undertaken an experimental investigation of a new methanation pathway aimed at avoiding the use of the solid catalyst, by exploring mechanisms involving a plasma generation by electrical discharges or by vacuum ultraviolet (VUV) photons on CO2+H2 gaseous mixtures. Preliminary measurements performed using a microwave discharge beam source developed in our laboratory gave useful indications on how to proceed to develop alternative solutions to the present Ni-catalysed apparatus by resorting to a gas-phase-only process for the reduction of CO2 to CH4. These results indicate that the chemical reactivity of plasmas containing CO2 should be strongly increased thanks to the presence of CO+ and O+ ions having a very high kinetic energy. These ionic species are produced via Coulomb explosion of CO22+ molecular dications by the same process responsible for the erosion of the atmosphere of Mars.