Ternary intermetallic LaCoSi as a catalyst for N2 activation

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 N-2 activation to produce NH3. The ammonia synthesis is significantly promoted by shifting the reaction bottleneck from the sluggish N-2 dissociation to NHx formation, which few catalysts have achieved. Theoretical calculations reveal that the negatively charged cobalt mediates electron transfer from lanthanum to the adsorbed N-2, which further reduces the activation barrier of N-2 dissociation. Most importantly, the specific LaCoSi geometric configuration stabilizes the N-2 adsorption with a strong exothermic effect, which dramatically decreases the apparent energy barrier of N-2 activation. Consequently, LaCoSi shows a superior activity (1,250 mu mol g(-1) h(-1)), with a 60-fold increase over the activity of supported cobalt catalysts under mild reaction conditions (400 degrees C, 0.1 MPa).