Unlocking the Selective Catalytic Conversion Processes of CO2 to Ethanol – UliSess

Every day, huge amounts of greenhouse gases (GHG) are emitted and accumulate in the atmosphere, which in turn causes global warming. Notably, carbon dioxide (CO2) contributes to 72% of the GHG emissions, mainly due to the combustion of large amounts of fossil resources, and its emissions keep rising. Therefore, carbon capture and utilization (CCU) and/or carbon capture and storage (CCS) are crucial in reducing CO2 emissions, a major air pollutant, and mitigating global warming. Of both, the CCU is a more attractive and promising pathway. Of the plethora of possible value-added chemicals, which can be produced from CO2, ethanol is an excellent choice. The latter is true due to its many uses e.g. as a clean fuel, engine fuel, fuel additive, intermediate of manufacturing industries, feedstock, solvent, low-temperature liquid etc. Ethanol production by fermentation is in many aspects considered non-ethical since it requires dedicated arable land (the food-versus-fuel discourse). Conversion of CO2 to ethanol can be achieved sustainably by direct hydrogenation using green hydrogen. In this project we will mitigate climate change in two steps, a) CO2 capture and utilization and, b) reduce the energy requrements in its purification. To achieve this, some issues have to be overcome, namely, CO2 activation and C-C coupling, which lead to low yields and unsatisfactory selectivity. Several studies have been published, that have overcome these issues to varying extent. However, the issues present drastically reduce the viability of direct CO2 hydrogenation, and encourage us to explore novel strategies for ethanol synthesis. In the proposed project we will tackle the issues described, by a multi-prong approach. We will investigate ethanol production via a) three distinct catalytic processes, will b) purify the ethanol (pilot scale) produced using state of the art extraction processes, and c) simulate all of the previous processes. We will arrive at this goal with a targeted approach. We will synthesize and fully characterize catlysts for all three catalytic processes. For the a) thermocatalytic (copper on zeolite based materials), b) electrocatalytic (polymetallic nanocatalysts supported on various materials), and c) the radiolytic approach (copper based catalysts). We will d) purify ethanol in the product mixture with multistage counter-current supercritical carbon dioxide extraction. Finally, we will e) define the approaches by first-principles simulations, kinetic description and mesoscopic simulations of membrane permeability. The latter will open a feedback loop, where the modelling results will be implemented in the next iteration of experiments. We expect to 1) identify the best performing catalyst (thermo- and electrocatalysis as well as radiolysis) supported on various materials and 2) determine how specific material properties affect the catalytic reaction. Additionally, we expect to 3) present in-depth understanding of how process parameters shift catalyst selectivity and activity, as well as stability. Furthermore, we believe we can reduce the 4) energy requirement in ethanol purification. And finally, with modelling, we anticipate we will 5) compose a multiscale model that will describe (predict) catalyst activity/selectivity and extraction efficiency. Ultimately, the results of the proposed project will further fundamental understanding of several catalytic as well as purification processes. This knowledge is not limited to ethanol production/purification and can be applied by researchers in other fields. The consortium is composed of outstanding researchers, foremost experts in their respective fields, therefore we expect to produce results of exceptional quality.