Electrochemical Synthesis of Methanol from  CO 2 in High‐Pressure Electrolyte

We synthesized from and on a copper cathode in the high‐pressure system. Methanol was the only product of reduction detected in the electrolytic solution, with a maximum current efficiency for methanol production of 40% at a current density of 9 mA/cm2 and potential of −1.1 V vs. Ag/AgCl. This is the highest efficiency yet reported for methanol production at this current density. Current‐potential curves shifted in the positive potential direction with increasing temperature and with increasing pressure up to approximately 60 atm. When the applied potential is more negative than about −1.2 V vs. Ag/AgCl, the current density decreases dramatically with time. Electrolyte conductivity in this system increases with increasing temperature, increasing concentration of LiCl, and decreasing pressure.