Molybdenum-based nitrogen carrier for ammonia production via a chemical looping route

Chemical looping ammonia synthesis (CLAS) is an innovative and effective method for sustainable ammonia generation, in which efficient N release/fixation of nitrogen carriers (NC) is required for successive ammonia production. Herein, we report a two-step CLAS mediated by a Mo2N-Mo couple and experimentally validate its N fixation and N release steps under mild conditions. In the N-release step, the NH3 production rate at 450 degrees C (> 4576 mu mol g(-1) h(-1)) was three times higher than that obtained via the thermo-catalytic ammonia synthesis route catalyzed by Mo2N. In the N-fixation step, the introduction of H-2 enhanced the reaction kinetics between Mo and N-2, accelerating NC regeneration. In addition, only a slight deactivation of NC was observed during the 8-cycle stability test. This study confirmed the preliminary feasibility of using Mo2N as an NC during the CLAS process.

Automated summary

Chemical looping ammonia synthesis (CLAS) using Mo2N as nitrogen carrier was demonstrated to be an effective and sustainable method for ammonia generation. The two-step CLAS showed high N release/fixation efficiency and achieved a higher NH3 production rate compared to the thermo-catalytic ammonia synthesis route catalyzed by Mo2N. The study also confirmed the stability and feasibility of using Mo2N as an NC during the CLAS process.