Selected-Ion Flow-Tube Mass Spectrometry (SIFT-MS) for Real-Time Quantitative Measurement of Electrochemical Carbon Dioxide Reduction Reaction Products

Electrochemical CO₂ reduction reaction (CO₂R) into fuels and chemicals is a promising route to help reduce greenhouse gas emissions and reach carbon dioxide net-zero emissions to combat climate change. Currently, the means of analyzing and quantifying catalytically produced CO₂R products from CO₂R rely on methods that only enable intermittent nonreal-time sampling, such as gas chromatography (GC) and nuclear magnetic resonance (NMR). The ability to have real-time analysis of the products generated from CO₂R is desirable, yet few analytical techniques have been developed to achieve this feature. Herein, we show the use of selected-ion flow-tube mass spectrometry (SIFT-MS) that quantitatively measures ten different C₁, and C₂₊ products produced via the CO₂R in real-time. The custom-developed SIFT-MS scan simultaneously measures the concentrations of the produced gas- and liquid-phase products and is compatible with any electrolyzer cell. We demonstrate that the SIFT-MS technique can reliably and accurately determine product concentration in real-time through the evaluation of Cu foil and its comparison to the literature and traditional product quantification techniques. Considering the narrow range of developed and deployed techniques for real-time quantitative product analysis for CO₂R, this study on SIFT-MS is a critical tool for future research in accelerating and optimizing catalyst design for electrochemical CO₂R applications.