N2 Reduction and Hydrogenation to Ammonia by a Molecular Iron-Potassium Complex
Abstract
The most common catalyst in the Haber-Bosch process for the hydrogenation of dinitrogen (N2) to ammonia (NH3) is an iron surface promoted with potassium cations (K+), but soluble iron complexes have neither reduced the N-N bond of N2 to nitride (N3-) nor produced large amounts of NH3 from N2. We report a molecular iron complex that reacts with N2 and a potassium reductant to give a complex with two nitrides, which are bound to iron and potassium cations. The product has a Fe3N2 core, implying that three iron atoms cooperate to break the N-N triple bond through a six-electron reduction. The nitride complex reacts with acid and with H2 to give substantial yields of N2-derived ammonia. These reactions, although not yet catalytic, give structural and spectroscopic insight into N2 cleavage and N-H bond-forming reactions of iron.
- Publication:
-
Science
- Pub Date:
- November 2011
- DOI:
- 10.1126/science.1211906
- Bibcode:
- 2011Sci...334..780R
- Keywords:
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- CHEMISTRY