An Online Gas Chromatography Cell Setup for Accurate CO2-Electroreduction Product Quantification

Abstract

The electrochemical reduction of carbon dioxide (CO2) constitutes an increasingly important scientific topic and research on novel electrocatalysts for this demanding reaction is constantly increasing. One of the most important properties to be inferred for such electrocatalysts is their product selectivity and potential dependence thereof. However, the wide range of materials currently employed in CO2 electroreduction (e.g., Ag, Cu, Pd) entails a large variety of gaseous and/or liquid reaction products for which accurate quantification implies a major challenge. With this motivation, in this study we present an online gas chromatography cell setup specifically designed for the accurate and reproducible determination of the product selectivities of CO2-reduction electrocatalysts. Therewith, we assess the parameters influencing the cell’s performance and point out important design features, such as reproducible electrode alignment, minimized contact resistances and a low ratio among electrolyte volume and the electrodes’ geometrical surface area. The setup was validated by performing measurements on a Pt nanoparticle catalyst for which H2 is the only expected reduction product, while a Pd nanoparticle catalyst was subsequently used to verify its capabilities for CO2 electroreduction selectivity measurements involving multiple liquid and gaseous products.