Carbon‐Negative Ammonia Production from the Air

Ammonia holds paramount importance as a fundamental chemical commodity for large‐scale production of fertilisers and hydrogen carriers. The conventional Haber–Bosch process relies heavily on fossil fuels, making ammonia synthesis a significant contributor to greenhouse gas emissions. Here, we show a carbon‐negative ammonia synthesis process that not only produces ammonia from the air but also directly captures the atmospheric CO 2 (DAC). This process uses lithium as a mediator to cleave the nitrogen gas via a nitridation reaction at ambient pressure below 80 °C. Exposing the nitride to moisture naturally yields ammonia. The co‐produced lithium hydroxide intermediate allows for spontaneous absorption of CO 2 with an exceptional capacity of 18.4 mmol CO 2 /g. The resultant lithium carbonate is electrolysed at ambient conditions to recycle the metallic lithium and release high‐purity gaseous CO 2 . This proof‐of‐concept of ammonia production from air coupled with DAC paves a new way for the development of sustainable and negative‐emission technologies.