Electrochemical synthesis of ammonia from wet nitrogen via a dual-chamber reactor using La0.6Sr0.4Co0.2Fe0.8O3−δ-Ce0.8Gd0.18Ca0.02O2−δ composite cathode

•Ammonia was synthesised directly from wet N2 at intermediate temperature.•Ammonia was synthesised from wet N2 using a dual-chamber reactor.•O2− ion conduction of the oxide-carbonate composite electrolyte was used.•Catalytic activity for ammonia synthesis is promoted by oxygen vacancies.

A La0.6Sr0.4Co0.2Fe0.8O3−δ-Ce0.8Gd0.18Ca0.02O2−δ composite cathode was used to investigate the electrochemical synthesis of ammonia from wet nitrogen. Wet nitrogen was flown through a dual chamber reactor under atmospheric pressure leading to the successful synthesis of ammonia. Ammonia was synthesised at a rate of 1.5 × 10−10 mol s−1 cm−2 at 400 °C when applying a dc voltage of 1.4 V, which is the highest reported to date. This rate is twice that of the observed ammonia formation rate (7 × 10−11 mol s−1 cm−2) when Co-free cathode, La0.6Sr0.4FeO3−δ-Ce0.8Gd0.18Ca0.02O2−δ was used as the cathode catalyst. A higher catalytic activity for ammonia synthesis may be obtained when using a catalyst with high oxygen vacancies, with the introduction of oxygen vacancies at the cathode being a good strategy to improve the catalytic activity of ammonia synthesis.

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