Theoretical Approach toward a Mild Condition Haber-Bosch Process on the Zeolite Catalyst with Confined Dual Active...

The Haber-Bosch (H-B) process is today's dominant technology for ammonia production, but achieving a mild reaction condition is still challenging. Herein, we combined density functional theory (DFT) calculations and microkinetic modeling (MKM) to demonstrate the feasibility of conducting the H-B process under ambient conditions on a zeolite catalyst with confined dual active sites. Our designed dual Mo(II) cation-anchored ferrierite [2Mo^(II)-FER] catalyst shows an energy barrier of only 0.58 eV for N≡N bond breaking due to the enhanced π-back-donation. Meanwhile, the three hydrogen sources (BH, FMH, and NMH) within 2Mo^(II)-FER greatly enrich the hydrogenation mechanisms of NH species, resulting in barriers of <1.1 eV for NH (x = 0-2) hydrogenations. This dual-site catalyst properly decouples the N₂ dissociation and NH hydrogenation steps, which elegantly circumvents the linear scaling relation between the N₂ dissociation barrier and the nitrogen binding energy. It is worth noting that our MKM results show 4 orders of magnitude higher reaction rates on 2Mo^(II)-FER than the stepped sites of the FCC Ru catalyst at low temperatures, paving a solid basis to conduct the H-B process at low temperatures. We believe that our strategy will provide crucial guidance for synthesizing state-of-the-art zeolite catalysts to achieve the near-ambient condition H-B process and other chemical reactions in heterogeneous catalysis.