Electrochemical Promotion of Ammonia Synthesis Integrated Directly with Steam Electrolysis

• Published in: Industrial & engineering chemistry research 2024-10, Vol.63 (40), p.17413-17418
• Main Authors: Okazaki, Moe, Otomo, Junichiro
• Format: Article
• Language: English
• ISSN: 0888-5885; 1520-5045
• DOI: 10.1021/acs.iecr.4c02192

Ammonia electrosynthesis using protonic ceramic electrolysis cells (PCECs) is predominantly conducted from hydrogen and nitrogen, necessitating a separate hydrogen production process. Herein, we demonstrate an integrated concept of conducting steam electrolysis at the anode while cofeeding nitrogen and hydrogen to the cathode, to accelerate ammonia formation via the electrochemical promotion of catalysis (EPOC). In practical applications, the hydrogen fed to the cathode can be obtained by recycling the hydrogen byproduct formed during the competing hydrogen evolution reaction, enabling accelerated ammonia production via EPOC without requiring an external hydrogen source. Using a simple iron catalyst and increasing the hydrogen fed to the cathode up to 50%, the ammonia formation rate was accelerated with applied voltage up to 7.2 × 10–9 mol s–1 cm–2. This integrated process has the potential to enable accelerated ammonia synthesis from water and nitrogen using a single electrochemical cell while also simplifying gas separation processes at the cathode.