Real-time Gas Chromatography and NMR Analysis of CO2 Electroreduction Products

In the cathode chamber, CO2 gas is introduced at a controlled flow rate of 100 mL/min. A peristaltic pump is used to extract the resulting gas at the same flow rate from the outlet, which is then continuously fed into the inlet of a gas chromatograph for real-time online analysis. The gas chromatograph is equipped with two detectors: a thermal conductivity detector (TCD) for measuring H2 and a flame ionization detector (FID) for detecting CO and CH4. The liquid products of the electroreduction are dissolved in deuterated dimethyl sulfoxide (DMSO-d6) with 0.03% tetramethylsilane (TMS) as an internal standard, and quantitatively analyzed using 1H-NMR spectroscopy on a nuclear magnetic resonance (NMR) spectrometer.