Fig. 4: Electrochemical CO₂/CO reduction performance of the Cu(100)-rich catalyst in a MEA electrolyzer.

a FEs for all products at various current densities and related cell potentials from CO₂ reduction. b Extended CO₂ electrolysis using the Cu(100)-rich catalyst at 300 mA cm⁻². Operating conditions: 0.1 M KHCO₃ anolyte (pH ~8.4) at a flow rate of 20 mL min⁻¹ and an average CO₂ inlet flow rate of ~75 sccm cm⁻² at atmospheric temperature and pressure conditions, in which the catalyst loading is ~1 mg cm⁻². c FEs for all products at various current densities and related cell potentials from CO reduction. d FEs as well as SPCEs toward C₂₊ products on the Cu(100)-rich catalyst at 500 mA cm⁻² with different CO flow rates. e Extended CO electrolysis using the Cu(100)-rich Cu catalyst at 500 mA cm⁻². The Cu(100)-rich catalyst delivers an average FE_C2+ of 86%, C₂₊ current densities of 432 mA cm⁻², EE_C2+ of 37%, and SPCE_C2+ of 94% throughout. Operating conditions: 1 M KOH anolyte (pH ~14) at a flow rate of 20 mL min⁻¹ and an average CO inlet flow rate of ~2 sccm cm⁻² at atmospheric temperature and pressure conditions, in which the catalyst loading is ~1 mg cm⁻².