The PSFD group focuses on conceptualization and development of commercially viable reactor concepts for plasma-based conversion of CO2 into solar fuels. The work is done in collaboration with industrial partners active in the energy grid infrastructure sector. The research revolves around plasma source development, characterization of its performance and integration in the established follow-up chemical processing and upscaling to grid-scale volumes.

Research in the solar fuels field evolved from early CO2 plasmolysis experimental campaigns in 2013, in cooperation with IGVP in Stuttgart. It was established that the high energy efficiencies of up to 90% under highly optimized low pressure conditions reported in literature are not directly compatible with industrial application. A multi-disciplinary approach was set out to address this challenge. The research of PSFD relies on a solid basis of microwave plasma engineering and diagnostics and combines fundamental fields of plasma physics and chemistry with an application oriented approach in a close cooperation with industry and academics. The research is devided in three categories.

Fundamentals of microwave plasma dissociation

Efficient plasma-driven conversion is enabled by a non-equilibrium process, which directs the plasma energy towards the relevant chemical reactions while suppressing unwanted loss-channels. Using this approach high conversion efficiencies of 90% have been reported in CO2 dissociation-optimized plasmas, under very narrow operational conditions. Development of methods for driving non-equilibrium conversion routes in the plasma reactors under less stringent operating conditions is essential for integration in chemical processing plants.

The plasma-dissociation of CO2 via vibrational excitation under VT-nonequilibrium conditions is studied by shaping the electric field in space and time. Important research topics are electric field optimization by microwave applicator design and high frequency power modulation by pulsing and beating with semiconductor microwave sources. 

Synthetic fuel production via advanced integrated reactor concepts  

Various pathways for creating synthetic fuels from feedstock of CO2 and H2O are researched. A promising approach involves plasmolysis of H2O and/or CO2 as feedstock for production of hydrogen, syngas or direct production of hydrocarbon fuels. Important is the development and integration of various technologies which enhances the overall conversion efficiency, rates and selectivity. Examples are capture and (intermediate) product separation with SOECs and integration of catalytically active materials to increase selectivity.

Industrial application and process integration

The PSFD group actively collaborates with industrial partners to work towards upscaling and integration in energy infrastructure. The work is aimed at integrating innovative plasma conversion concepts with industrial processes. Important aspects of research are optimization of plasma conditions in high-capacity reactor concepts, the conversion efficiency on a whole-system perspective including waste heat reutilization and integration of cutting-edge high power solid state source technology. Physical upscaling of the reactor design is accomplished by in-house development of microwave plasma research reactors from current kW scale towards 10-50 kW capacity in the near future.