AUTHOR=Garagounis Ioannis , Kyriakou Vasileios , Skodra Aglaia , Vasileiou Eirini , Stoukides Michael 

TITLE=Electrochemical Synthesis of Ammonia in Solid Electrolyte Cells

JOURNAL=Frontiers in Energy Research

VOLUME=2

YEAR=2014

URL=https://www.frontiersin.org/journals/energy-research/articles/10.3389/fenrg.2014.00001

DOI=10.3389/fenrg.2014.00001

ISSN=2296-598X

ABSTRACT=<p>Developed in the early 1900s, the “Haber–Bosch” synthesis is the dominant NH<sub>3</sub> synthesis process. Parallel to catalyst optimization, current research efforts are also focused on the investigation of new methods for ammonia synthesis, including the electrochemical synthesis with the use of solid electrolyte cells. Since the first report on Solid State Ammonia Synthesis (SSAS), more than 30 solid electrolyte materials were tested and at least 15 catalysts were used as working electrodes. Thus far, the highest rate of ammonia formation reported is 1.13 × 10<sup>-8</sup> mol s<sup>-1</sup> cm<sup>-2</sup>, obtained at 80°C with a Nafion solid electrolyte and a mixed oxide, SmFe<sub>0.7</sub>Cu<sub>0.1</sub>Ni<sub>0.2</sub>O<sub>3</sub>, cathode. At high temperatures (&gt;500°C), the maximum rate was 9.5 × 10<sup>−9</sup> mol s<sup>-1</sup> cm<sup>-2</sup> using Ce<sub>0.8</sub>Y<sub>0.2</sub>O<sub>2-δ</sub>–[Ca<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub>–K<sub>3</sub>PO<sub>4</sub>] as electrolyte and Ag–Pd as cathode. In this paper, the advantages and the disadvantages of SSAS vs. the conventional process and the requirements that must be met in order to promote the electrochemical process into an industrial level are discussed.</p>