2020/08/07 by Tian‐Nan Ye, Sang‐Won Park, Yangfan Lu +4 · 2 citations
Chemical Engineering · Chemistry · Materials Science · #Ammonia Synthesis and Nitrogen Reduction #Hydrogen Storage and Materials #Nanomaterials for catalytic reactions
paper · doi:10.1021/jacs.0c06624
openalex publication_date 2020/08/07 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30
Ammonia is one of the most important feedstocks for the production of fertilizer and as a potential energy carrier. Nitride compounds such as LaN have recently attracted considerable attention due to their nitrogen vacancy sites that can activate N 2 for ammonia synthesis. Here, we propose a general rule for the design of nitride-based catalysts for ammonia synthesis, in which the nitrogen vacancy formation energy ( E NV ) dominates the catalytic performance. The relatively low E NV (ca. 1.3 eV) of CeN means it can serve as an efficient and stable catalyst upon Ni loading. The catalytic activity of Ni/CeN reached 6.5 mmol·g –1 ·h –1 with an effluent NH 3 concentration ( E NH3 ) of 0.45 vol %, reaching the thermodynamic equilibrium ( E NH3 = 0.45 vol %) at 400 °C and 0.1 MPa, thereby circumventing the bottleneck for N 2 activation on Ni metal with an extremely weak nitrogen binding energy. The activity far exceeds those for other Co- and Ni-based catalysts, and is even comparable to those for Ru-based catalysts. It was determined that CeN itself can produce ammonia without Ni-loading at almost the same activation energy. Kinetic analysis and isotope experiments combined with density functional theory (DFT) calculations indicate that the nitrogen vacancies in CeN can activate both N 2 and H 2 during the reaction, which accounts for the much higher catalytic performance than other reported nonloaded catalysts for ammonia synthesis.