We investigated the ECR catalysts using a lab-customised 3D-printed electrolyser flow cell, as shown in Figure in the Supplementary Information. The catalysts were deposited on a carbon paper GDL substrate, with Ag/AgCl and Pt foil serving as the reference and counter electrodes, respectively. CO2 gas was introduced into the gas chamber via a gas inlet and diffused across the GDL to reach the catalyst layer. The CO2 gas flow rate was maintained at a constant 50 mL min -1 using a flow meter (Cole-Parmer TMR1-010462). A Fumasem FBM bipolar membrane was used between the cathodic and anodic compartments to allow the transfer of cations. Platinum foil was used as the anode. After 30 minutes of CO2 electrolysis, the gas products were collected from the gas outlet for GC measurements, and the catholyte was collected for liquid product analysis using ion chromatography. To investigate the ECR behaviour of CTC-65 electrodes, we conducted chronoamperometry (CA) tests for 1 hour at potentials of -0.5 V, -0.65 V, -0.75 V, -0.85 V, and -1.00 V vs. RHE. The Faradaic efficiency (FE) of the electrochemical reaction was estimated from the CA measurements by considering the input charge, the duration of the electrochemical process, and the quantification of the gaseous/liquid products and their molar masses.