Vaste-stof elektrolyten en CO2 sorberende materialen for gas diffusie electrodes

Global warming as a result of industrial age CO2 emissions is a prime societal concern with a growing popular awareness calling for policy measures. A behavioral change is important, but technology also needs to come with solutions to reduce emissions and, hopefully, even reverse it. Indeed, with a rapidly growing world population and continuous increase in energy demand, it is understood that a lone switch to renewable energies will not suffice to keep the temperature rise well below +2oC above pre-industrial levels. In addition, carbon dioxide is not only a product of energy by combustion, but a waste product of chemical industry as well. For example, the cement industry is responsible for 10% of carbon emissions, with about half of that as by-product of the lime production process itself. Therefore, a technology that can convert CO2 into valuable products by electrolysis, would turn CO2 into a valuable precursor and give it economic value. At imec we are looking into concepts for simultaneous capture and conversion of CO2 directly from air or point sources such as factory chimneys to enable residential and industrial installations for local production of renewable fuels and synthesis of fine chemicals. At large scale, it will help reduce CO2 emissions and could be the technological instrument to eventually reverse the trend with 'negative emissions'. Hydrophobic gas diffusion-layer electrodes (GDE) are used to achieve high throughput of an electrolysis reactor, e.g. for CO2 reduction. Conventional GDE have one side exposed to the gas ambient (hydrophobic side) and the other immersed in solution where also the counter electrode or anode is placed. Gasses dissolve in the thin layer of liquid that impregnates the microporous catalyst layer where they can react electrochemically. As such, the CO2 diffusion distance can be reduced to a few hundreds of nanometers in state-of-the-art GDE allowing current densities up to few hundreds of mA/cm2. However, the GDE are limited to gas ambients with high partial CO2 pressure close to 1 bar. Flue gasses only contain about 0.1bar of CO2. Hence, materials are needed that can adsorb and concentrate the CO2 for further reaction. These sorbent materials together with solid electrolyte materials will enable future all-gas-phase GDE for direct capture and conversion of CO2 to valuable molecules.