Abstract: The application of electrochemical carbon dioxide reduction reaction (CO₂RR) to produce ethylene has attracted much research interest in the field of electrocatalytic CO₂RR. A cubic Cu₂O catalyst with abundant (111) crystal faces was successfully prepared by a simple chemical precipitation coupled chemical reduction protection method. In addition, electrochemical properties of cubic Cu₂O catalysts in an H-type reactor and zero-gap membrane electrode assembly(MEA) reactor were systematically studied. The results revealed several points. First, the Cu₂O catalyst with abundant (111) crystal faces showed excellent ethylene production capabilities. Second, when compared with H-type reactor, the optimal Faradaic efficiency (FE) of zero-gap MEA reactor for CO₂RR was increased by 13.94%, and its total current density satisfied industrialization requirements (>200 mA/cm2 ). In addition, the large-area (25 cm2 ) zero-gap MEA reactor was designed and assembled in this work, and results showed the excellent catalytic performance at CO₂RR and a unique “area effect” above 2.9 V. The appearance of the “area effect” indicates that the current density of the catalytic reaction may be affected by the plate channel design and conductivity optimization in addition to the adjustment of the electrode area, electrolyte concentration, CO₂ flow rate and other key factors when the effective area of the zero-gap MEA reactor is enlarged. 

Key words:  electrochemical carbon dioxide reduction reaction (CO₂RR), Cu₂O catalysts; (111) crystal faces, zero-gap membrane electrode assembly(MEA) reactor, area e?ect