Robust and efficient electroreduction of CO2 to CO in a modified zero-gap electrochemical cell

• Higher temperature or pressure in the zero-gap electrolyzer enhances mass transport and reaction kinetics. • Low voltage at high current density boosts energy efficiency to 52.6% in alkaline and 49.4% in neutral conditions. • Microenvironment management prevents carbonate accumulation, maintaining 90% FE CO over 100 hours. Excellent energy efficiency and system stability are critical factors guiding the practical application of carbon dioxide reduction reaction (CO 2 RR) systems. This work promotes reduction reaction kinetics in a modified zero-gap electrolyzer by regulating the operation temperature and pressure. The energy efficiency of the CO 2 RR system is enhanced, such as 52.6 % at a current of 1.2 A under alkaline conditions and 49.4 % under neutral conditions, with the characteristics of low voltage and high Faradaic efficiency. In addition, the optimization of the reaction microenvironment effectively alleviates the precipitation issue, enabling the system to operate stably for more than 100 h, with a Faradaic efficiency of more than 90 % for CO generation. Engineering-integrated electrochemistry inspires the future development of CO 2 RR technology.