Activating high-energy multiple bonds using earth-abundant metals is one of the most significant challenges in catalysis. Here, we show that LaCoSi—a ternary intermetallic compound—is an efficient and stable catalyst for N2 activation to produce NH3. The ammonia synthesis is significantly promoted by shifting the reaction bottleneck from the sluggish N2 dissociation to NH x formation, which few catalysts have achieved. Theoretical calculations reveal that the negatively charged cobalt mediates electron transfer from lanthanum to the adsorbed N2, which further reduces the activation barrier of N2 dissociation. Most importantly, the specific LaCoSi geometric configuration stabilizes the N2 adsorption with a strong exothermic effect, which dramatically decreases the apparent energy barrier of N2 activation. Consequently, LaCoSi shows a superior activity (1,250 μmol g−1 h−1), with a 60-fold increase over the activity of supported cobalt catalysts under mild reaction conditions (400 °C, 0.1 MPa).
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This work was supported by the Accelerated Innovation Research Initiative Turning Top Science and Ideas into High-Impact Values (ACCEL) programme of the Japan Science and Technology Agency. H.H. was supported by the Japan Society for the Promotion of Science through a Grant-in-Aid for Scientific Research (S), No.17H06153. The authors thank S. Fujitsu (Tokyo Institute of Technology) for technical support with the Auger electron spectroscopy measurements.
The authors declare no competing financial interests.
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Gong, Y., Wu, J., Kitano, M. et al. Ternary intermetallic LaCoSi as a catalyst for N2 activation. Nat Catal 1, 178–185 (2018). https://doi.org/10.1038/s41929-017-0022-0
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