Synthesis of ammonia from water and nitrogen using a compo-site cathode based on La0.6Ba0.4Fe0.8Cu0.2O3-δ-Ce0.8Gd0.18Ca0.02O2-δ

Abstract

Carbon-free electrochemical synthesis of ammonia is a promising technology for CO2 emission reduction. This study aims to explore the electrocatalytic activity of A-site Ba-doped perovskite cathode catalyst (La0.6Ba0.4Fe0.8Cu0.2O3-δ, LBFCu) for ammonia synthesis from water and nitrogen. LBFCu was prepared via the sol-gel method using combined EDTA-citrate complexing agents and characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). Ammonia was successfully synthesised from water and nitrogen under atmospheric pressure, and LBFCu mixed with Ce0.8Gd0.18Ca0.02O2-δ (CGDC) was used as a cathode. When a voltage was applied to the cell containing CGDC-carbonate composite solid electrolyte, ammonia formation was observed at 375, 400, 425 and 450 °C. At 400 °C and 1.4 V, the maximum rate of ammonia production was achieved at 4.0×10-11 mol s-1 cm-2, which corresponds to Faradaic efficiency of ~ 0.06 % at the current density of 19 mA cm-2. According to the findings, the synthesis of ammonia directly from water and nitrogen may be considered a promising green synthesis technology.