(726e) Porous Metallic Membranes As High-Performance Cathodes for CO2 Reduction | AIChE

(726e) Porous Metallic Membranes As High-Performance Cathodes for CO2 Reduction


Larrazábal, G. O. - Presenter, Technical University of Denmark
Zeiter, K., ETH Zurich
Baier, S., Technical University of Denmark
Clark, E. L., Technical University of Denmark
Therkildsen, K. T., Siemens A/S
Chorkendorff, I., Technical University of Denmark
Seger, B., Technical University of Denmark
Combining the electrochemical reduction of CO2 (eCO2RR) with carbon-neutral energy sources creates groundbreaking possibilities for using CO2 as a raw material for the sustainable production of fuels and chemicals. In particular, its efficient reduction to carbon monoxide and to ethylene at high current densities would provide key building blocks in a future fossil fuel-free chemical industry.

Recent reports using gas diffusion electrodes (GDEs) have demonstrated the viability of carrying out the eCO2RR at industrially relevant reaction rates, but more insights into the influence of cell design and electrode structure are needed to guide further upscaling efforts. In this presentation, we will discuss our recent work using carbon-free metallic membranes as cathodes for CO2 reduction in a vapor-fed electrolytic device. When combined with a Sustainion anion exchange membrane (AEM) in a membrane electrode assembly (MEA), porous silver membranes can sustain high rates of CO2 reduction to CO (ca. 250 mA/cm2 at a cell voltage of 3.1 V) with negligible hydrogen evolution. Furthermore, the homogeneous structure of these membranes provides an ideal platform to study the influence of the electrode pore network on the performance of CO2 reduction electrolyzers. We will discuss the eCO2RR performance of porous copper GDEs and describe how the morphology of the electrodes and the availability of different catalytic sites can be tuned via the synthetic procedure. In addition, we will show how the analysis of both cathodic and anodic outlet flows is key for a more complete understanding of CO2 reduction at high current densities in electrolytic devices, and experimental strategies in this regard will be presented.