Real-Time Detection and Quantification of Gaseous Products in a GDE Setup: CO₂ to Ethylene

The electrochemical carbon dioxide reduction reaction (CO2RR) is gaining significant attention as a promising solution to convert carbon emissions and intermittent solar and wind electricity into value-added building block chemicals and fuels. While advanced approaches such as gas diffusion electrodes (GDE) have achieved economically relevant reaction rates (>500 mA/cm2), they unfortunately exhibit poor long-term stability, which is preventing industrial-scale CO2RR implementation. We report a novel analytical setup that utilizes a parallel configuration of mass spectrometry and gas chromatography to enable accurate detection and quantification of major CO2RR gaseous products at industrially relevant partial current densities (>200 mA/cm2). The achieved sub-second resolution allows us to fully evaluate catalytic materials in extremely short time frames (<10 min) as well as reliably monitor product distribution shifts under intrinsic and induced dynamic conditions. Ultimately, this work presents a powerful tool that can help understand the intrinsic limitations of the GDE approach as well as drive the development of more efficient and stable electrolysis systems for the CO2RR and similar processes.