The gases H2 and CO produced at the cathode were detected and quantified using a Shimadzu GC-2010 Plus gas chromatogram with ultrapure Helium as the carrier gas. 2% CH4 in the purging N2 gas after CO2 capture was used as an internal standard for quantification. Gaseous aliquots were taken from the headspace and were analysed by manual injection to the GC. The liquid aliquots from both cathodic and anodic compartments were taken after the experiments, and then analysed by 1 H NMR spectroscopy or HPLC. A Waters breeze HPLC system equipped with a Phenomenex Rezex 8% H + column and refractive index (RIS-2414) and diode array UV-Vis (254 nm) detectors was used for the oxidation product quantification. The faradic efficiencies (FE) of products were determined from equation 7,