Laassiri Said, Zeinalipour-Yazdi Constantinos D, Bion Nicolas, Catlow C Richard A, Hargreaves Justin S J
Univ. Lille, CNRS, ENSCL, Centrale Lille, Univ. Artois, UMR 8181, UCCS - Unité de Catalyse et Chimie du Solide, F-59000, Lille, France.
School of Science, University of Greenwich, Central Avenue, Chatham Maritime, Kent, ME4 4TB, UK.
Faraday Discuss. 2021 May 1;229:281-296. doi: 10.1039/c9fd00131j. Epub 2021 Mar 17.
Manganese nitride related materials are of interest as two-stage reagents for ammonia synthesis via nitrogen chemical looping. However, unless they are doped with a co-cation, manganese nitrides are thermochemically stable and a high temperature is required to produce ammonia under reducing conditions, thereby hindering their use as nitrogen transfer materials. Nevertheless, when lithium is used as dopant, ammonia generation can be observed at a reaction temperature as low as 300 °C. In order to develop strategies for the improvement of the reactivity of nitride materials in the context of two-stage reagents, it is necessary to understand the intrinsic role of the dopant in the mechanism of ammonia synthesis. To this end, we have investigated the role of lithium in increasing the manganese nitride reactivity by in situ neutron diffraction studies and N and H isotopic exchange reactions supplemented by DFT calculations.
氮化锰相关材料作为通过氮化学循环合成氨的两步试剂备受关注。然而，除非掺杂共阳离子，氮化锰在热化学上是稳定的，在还原条件下需要高温才能产生氨，从而阻碍了它们作为氮转移材料的应用。尽管如此，当使用锂作为掺杂剂时，在低至300°C的反应温度下就能观察到氨的生成。为了在两步试剂的背景下制定提高氮化物材料反应活性的策略，有必要了解掺杂剂在氨合成机理中的内在作用。为此，我们通过原位中子衍射研究以及辅以密度泛函理论计算的氮和氢同位素交换反应，研究了锂在提高氮化锰反应活性中的作用。
