Ammonia Synthesis from Nitrogen and Water by Electricity Using an Electrochemical Cell with Ru Catalyst, Hydrogen‐Permeable Pd‐Ag Membrane, and Phosphate‐Based Electrolyte

Conversion from renewable energy‐based electricity to chemical fuels is a promising technology in the near future. NH 3 is one of the candidates as chemical energy carriers, which can be synthesized from N 2 and H 2 O using electricity. A new NH 3 synthesis from N 2 and H 2 O by electricity at 250 °C using an electrochemical cell that consists of a Ru/Cs + /MgO catalyst, Pd−Ag membrane cathode, a CsH 2 PO 4 /SiP 2 O 7 electrolyte, and Pt anode has been proposed in this work. An NH 3 synthesis rate of 7.7×10 −10  mol s −1  cm −2 was obtained at 6.4 mA cm −2 and 1.2 V under a flow of N 2 at 1 cm 3  min  −1 . The current efficiency for NH 3 synthesis was 3.5%, and the other part was used for H 2 formation. The examination depending on the flow rate of N 2 was demonstrated and the small flow of N 2 was found to be preferred for NH 3 synthesis. The present cell is expected to open up new perspectives in the developments of the most suitable materials as NH 3 catalysts, hydrogen membranes, and water electrolyzer for combination in a reactor at the intermediate temperature.