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Technical Photosynthesis by Combining Electrochemical Reduction of CO2 and Anaerobic Fermentation

Invitation to lecture with guest speaker Dr. Guenter Schmid, Siemens AG - Corporate Technology, Erlangen (D)

Profitable renewable synthesis of chemicals and fuels is a prerequisite for its implementation into current economics. Boundary conditions for the synthesis sequence are the availability of renewable energy in sufficient quantities and its intermittent character. Profitability is difficult when considering the low fossil energy carrier prices and the physical efficiency limitations of the processes. The presented industrial process consists of two major components: Firstly, electricity from wind or solar is stored by electrolysis into energy carriers like hydrogen (H2) or carbon monoxide (CO). Current density, Faradaic and electrical efficiency and endurance of this upstream process will be discussed. Secondly downstream, a flexible mixture of CO, CO2 and H2 is supplied to a multistep anaerobic fermentation process, whereas they are initially converted to acetic acid and ethanol with high carbon efficiency and thus almost without any undesired by-products. The todays economic value is obtained by further condensation of the C2 products to C4 and C6 special chemicals (carboxylates and alcohols). Eventually, finally scaled into the hundreds megawatt range the molecules can be used as fuels. In the talk a potential solution is addressed by using a commercially available silver-based gas diffusion electrode (used in industrial-scale chlorine–alkaline electrolysis) as the cathode in the CO2 electrolyser. Electric current densities up to 300 mA cm² were demonstrated for more than 1,200 hours with continuous operation. Faradaic efficiency of the anaerobic fermentation processes was almost quantitative [1]. Evonik and Siemens have decided to bring the technology toward an industrial scale. The project is named Rheticus [2]. Generally, such an approach is called artificial or technical photosynthesis.

[1] Haas et al. Technical photosynthesis involving CO2 electrolysis and fermentation; Nature Catalysis 2018, Vol 1. pp 32–39, to the article
[2] press release Evonik; press release Siemens

Datum und Zeit

15.09.2020 12:30 - 13:30 iCal


FHNW Campus Muttenz

Veranstaltet durch

Hochschule für Life Sciences
Institut für Chemie und Bioanalytik


Eintritt frei

Event Sprache

Deutsch oder Englisch

Hochschule für Life Sciences FHNW

Fachhochschule Nordwestschweiz FHNW Hochschule für Life Sciences Hofackerstrasse 30 4132 Muttenz
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