Enhancement of lithium-mediated ammonia synthesis by addition of oxygen

• DOI: 10.1126/science.abl4300
• Publication Date: 2021-12-23T18:55:56Z
• Authors: Katja Li; Suzanne Z. Andersen; Michael J. Statt; Mattia Saccoccio; Vanessa J. Bukas; Kevin Krempl; Rokas Sažinas; Jakob B. Pedersen; Vahid Shadravan; Yuanyuan Zhou; Debasish Chakraborty; Jakob Kibsgaard; Peter C. K. Vesborg; Jens K. Nørskov; Ib Chorkendorff
• Keywords: Ammonia production; Oxygen evolution

Owing to the worrying increase in carbon dioxide concentrations atmosphere, there is a need electrify fossil-fuel–powered chemical processes such as Haber-Bosch ammonia synthesis. Lithium-mediated electrochemical nitrogen reduction has shown preliminary promise but still lacks sufficient faradaic efficiency and formation rate be industrially relevant. Here, we show that oxygen, previously believed hinder reaction, actually greatly improves stability of lithium-mediated when added reaction atmosphere small amounts. With this counterintuitive discovery, reach record high efficiencies up 78.0 ± 1.3% at 0.6 0.8 mole % oxygen 20 bar nitrogen. Experimental x-ray analysis theoretical microkinetic modeling shed light on underlying mechanism.