Carbon dioxide (CO2) is the primary contributor to climate change, and there is globally ongoing effort to reduce CO2 emissions. CO2 can be converted to valuable products using various methods, for example with chemical or biological conversion. A novel mechanism is microbial electro-synthesis (MES), in which electrochemically active microbes use renewable electricity to convert CO2 in organic molecules, such as fuels (Figure 1).
MES is considered more efficient and sustainable than photosynthetic bio-fuel production, but still faces challenges that limit its application, related to the poor transfer of electrons from the cathode electrode to the microbes, the narrow product spectrum and low product separation efficiency. The objective of this project is to overcome these limitations, by combining electro-chemical and bio-electro-chemical conversion of CO2.
Highlight of the past year
During this year, the first modified cathodes with electro-catalysts have been prepared and characterized in terms of surface structure and catalytic activity. Abiotic tests have already yielded improvement of the electrochemical performance. As shown in Figure 2, the flow of electrons over time (i.e. current), one of the limiting factors of MES, increases significantly when a modified cathode is used, compared to control tests. Currently, the effect of electro-catalysts in biological systems is investigated, in experimental reactors as shown in Figure 1.
Type of student projects envisioned
Research topics can involve both modeling and laboratory methodology. Modeling of the individual and combined catalytic processes could enhance the understanding of this complex reactor. New cathodes with different preparation methods, catalysts, and support materials will be investigated, using chemical, spectroscopic, and surface characterization techniques. Long-term bio-electro-chemical experiments will be performed to investigate the effect of environmental and biological factors.