(246c) Ab-Initio Design of Mild Temperature Ammonia Synthesis Catalysts Using Ni-Supported Metal Nitrides
AIChE Annual Meeting
2024
2024 AIChE Annual Meeting
Catalysis and Reaction Engineering Division
Fundamentals of Catalysis and Surface Science IV: Metal, Bimetallic, and Single Atom Catalysts
Tuesday, October 29, 2024 - 8:36am to 8:54am
We explored the correlation between ammonia adsorption energy and nitrogen vacancy formation energy for metal nitrides, crucial for understanding their catalytic behavior. Additionally, we investigated the influence of a quasi-one-dimensional Ni nanowire supported on a MnN substrate. The application of the nudged elastic band method on this system revealed a simplified ammonia formation mechanism, elucidating the potential of nanoparticles in enhancing catalytic efficiency. Through a detailed microkinetic model, we quantified reaction rates and species concentrations on Ni/MnN metal nitride surfaces, validated against experimental data for accuracy. Ultimately, we evaluated different phases and surfaces of manganese nitrides, constructing a surface phase diagram to determine the most energetically favorable structure under reaction conditions of nitrogen and hydrogen thermodynamic reservoirs. This ab-initio thermodynamic analysis guides the establishment of temperature and pressure conditions crucial for our chemical looping approach with metal nitride catalysts. By facilitating dynamic replenishment of vacancies in metal nitrides through phase transitions, this method enhances ammonia yields and offers catalyst regeneration potential.
Our research delves into the surface and reaction chemistry of metal nitrides, laying the groundwork for catalysts to produce higher ammonia yields under mild temperature and pressure conditions.