Low concentration CO2 electroreduction was performed on CoPL immobilised on MWCNT as a molecular catalyst (see Figure ). CoPL was chosen based on its known CO selectivity during electroreduction of pure CO2, and stability when immobilised on MWCNT via π-π stacking and its lipophilic alkyl chains (see Supplementary Note 1, and Figures ). We therefore further explored the electroreduction ability of CoPL supported on MWCNT under variable CO2 concentrations ranging 10, 20, 50 and 100 vol% (balanced with N2), using an electrochemical flow setup that allowed continuous purging of the electrolyte solution with a given gas composition. Cathodes containing CoPL were prepared, following a reported procedure (see Figure ), by drop-casting a dimethylformamide (DMF) suspension containing 2.37 mg MWCNT mL -1 and 0.1 mM CoPL onto carbon paper (CP) (0.1 mLDMF cm -2 , geometrical surface area = 1 cm 2 ), which is denoted as CP|CoPL. Electrocatalysis with CP|CoPL was performed in a twocompartment electrochemical cell with a three-electrode setup. Pt foil was used as counter electrode (CE) and Ag/AgCl (sat. KCl) as reference electrode (RE), a Nafion membrane separating the cathode and anode chambers, with the catholyte (0.1 M NaHCO3 in H2O) under a constant gas flow (9 mL min -1 ) of CO2 and N2 regulated by mass flow controllers. The generated gaseous products during electrochemical experiments (H2 and CO) were measured via online GC (schematically represented in Figure ). During chronoamperometry (CA) experiments, under an applied potential of -1.2 V vs.