Direct quantification of electrochemical CO₂ reduction products with an improved DEMS setup

The analytical tools to quantify CO₂RR products are often slow and have high limits of detection. As a result, researchers are forced to extend the duration of their experiments to accumulate sufficient product and surpass these detection limits. This slows down research considerably, and the research scope often remains limited. To help speed up CO₂RR catalyst studies, we have developed a new differential electrochemical mass spectrometer (DEMS) setup and cell design that enables the quantification of major gaseous and liquid products significantly faster than conventional analytical techniques. Special attention was given to the hydrodynamics of the cell to avoid mass transfer limitations and the calibration of the setup to accurately quantify the major CO₂ reduction products. As proof of concept of the methodology, the products formed during CO₂RR on a polycrystalline Ag and Cu electrode in a 0.1-M KHCO₃ electrolyte at different potentials were measured and quantified.