Study on Fe/BZY Cathode Catalysts for Intermediate‐Temperature Electrochemical Ammonia Synthesis Using Solid Phosphate Electrolytes

ABSTRACT Electrochemical NH 3 synthesis was conducted at intermediate temperatures ( ca . 220°C) using a cell with a Cs phosphate–based electrolyte. A Fe/BZY (yttrium‐doped barium zirconate) cathode catalyst was developed by combining Fe 2 O 3 /BZY reduced at 500°C and 800°C in a 1:1 weight ratio, which enabled NH 3 formation. Metallic Fe formed above 700°C was found to serve as an electronic conduction path in the cathode. Furthermore, K addition to the developed cathode enhanced the NH 3 production rate to 1.3 × 10 −10 mol s −1 cm −2 at −1.0 V (vs. OCV). This study demonstrates the first electrochemical NH 3 synthesis using a base‐metal cathode with a solid‐state Cs phosphate electrolyte.