Electrochemical Synthesis of Ammonia in Molten Salt Electrolyte Using Hydrogen and Nitrogen at Ambient Pressure

Abstract

In this study, the synthesis of ammonia (NH3) at ambient pressure using H2 and N2 is electrochemically achieved. The conducting and reaction media with molten salt consist of molten hydroxide as NaOH and KOH whereas the reaction temperature is varied in the range of 200°C to 255°C to investigate the impact of temperature on the ammonia production rate and hence performance. The porous nickel mesh electrodes having an area of 100 cm2 are used as cathode and anode where the supplied electricity is controlled using potentiostat/galvanostat. The maximum faradaic efficiency for ammonia synthesis is found to be 9.3% at 210°C corresponding to 6.53 × 10−10 mol/s cm2 ammonia evolution rate at 2 mA/cm2 current density with nano-Fe3O4 as the catalyst. Furthermore, the applied voltages and applied currents are varied to find the optimum experimental conditions for molten salt electrolyte based electrochemical ammonia synthesis.