Curbing further global warming is probably the greatest challenge currently facing mankind. To achieve this, greenhouse gas emissions must be drastically reduced. These greenhouse gases are released when fuels, chemicals and plastics are obtained from fossil raw materials in the same way as before.

If this is to be avoided, the carbon cycles of these products must be closed with the help of modern technologies. These are summarized under the generic term „Carbon Capture and Utilization“ (CCU). These innovative processes use captured CO2 from industrial emissions as a raw material and renewable energy sources to produce fuels, chemicals or plastics from the CO2. In the future, CO2 will also be extracted directly from natural sources to create a more sustainable industry.

CO2 electrolysis offers a promising option for utilizing the captured CO2. In this process, CO2 is electrochemically converted into valuable substances such as carbon monoxide (CO) or ethylene. CO is a key component in the production of fuels and chemicals, while ethylene forms the basis for many plastics. The current market for CO is estimated at 2.8 billion euros and that for ethylene at 215 billion euros. Both substances are currently still obtained from fossil sources, which has a significant impact on the environment.

To further develop this technology, we are researching advanced reactors that can convert CO2 continuously and efficiently. To this end, CO2 electroreduction is being optimized on a smaller scale and then scaled up. One promising and scalable approach is the zero-gap reactor architecture, which is known from water electrolysis. Here, the electrodes and catalyst layers are in direct contact with the membrane, the solid electrolyte, and form a so-called membrane-electrode unit. This technology is still at an early stage of development and further research is needed to improve its product yield, energy efficiency and long-term stability.

In particular, we are testing and researching whether increasing the pressure of the CO2 stream makes CO2 electrolysis more efficient and selective. To this end, we have developed a high-pressure reactor that makes it possible to increase the pressure of the CO2 to up to 200 bar(g). The increased pressure ensures that more CO2 molecules are available on the catalyst surface for the reaction, which increases efficiency and reduces unwanted side reactions. After optimizing the membrane electrode unit, our reactor will be scaled up to bring the technology closer to industrial applications.