This paper reports a novel electrochemical oxygen separation process using a hydroxide ion conductor as an electrolyte. In this study, we used Ni-Fe layered double hydroxide (LDH) intercalated with CO32- (Ni-Fe CO32- LDH) as a hydroxide ion conductive material. Ni-Fe CO32- LDH was prepared using the co-precipitation method. Electrodes using Pt/C as a catalyst and Ni-Fe CO32- LDH as an ionomer were prepared and a membrane reactor for oxygen separation using Ni-Fe CO32- LDH as an electrolyte was fabricated. The electrochemical oxygen product flow was confirmed to be proportional to the external current density, and thus the membrane functioned at 50 degrees C under 70% of relative humidity and an electrical potential gradient. (C) 2013 Elsevier B.V. All rights reserved.