High Ammonia Adsorption in MFM-300 Materials: Dynamics and Charge Transfer in Host-Guest Binding
High Ammonia Adsorption in MFM-300 Materials: Dynamics and Charge Transfer in Host-Guest Binding
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DOI：
10.1021/jacs.0c11930
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发表时间：
2021-02-19
影响因子：
15
通讯作者：
Schroder, Martin
中科院分区：
文献类型：
--
作者：
Han, Xue;Lu, Wanpeng;Schroder, Martin
氨（NH3）由于其高氢密度而成为一种有前途的能源。然而，由于缺乏高效、耐腐蚀的存储材料，限制了其广泛应用。在这里，我们报告了一系列坚固的金属有机框架（MOF）材料MFM-300（M）（M = Fe，V，Cr，In）中的高NH3吸附。MFM-300（M）（M = Fe、V-III、Cr）在273 K和1 bar下显示出超过20次循环的完全可逆容量，分别达到16.1、15.6和14.0 mmol g（-1）的容量。在相同的条件下，MFM-300（V-IV）在这一系列的MOFs中表现出最高的吸收，为17.3 mmol g（-1）。原位中子粉末衍射、单晶X射线衍射和电子顺磁共振光谱证实，具有氧化还原活性的V中心能够实现主客体电荷转移，其中V-IV被还原为V-III，NH3被氧化为肼（N2 H4）。原位非弹性中子散射和DFT建模的组合揭示了这些MOF内吸附的NH3的结合动力学，以提供对MOF材料在NH3的吸附和转化中的应用的全面了解。
Ammonia (NH3) is a promising energy resource owing to its high hydrogen density. However, its widespread application is restricted by the lack of efficient and corrosion-resistant storage materials. Here, we report high NH3 adsorption in a series of robust metal-organic framework (MOF) materials, MFM-300(M) (M = Fe, V, Cr, In). MFM-300(M) (M = Fe, V-III, Cr) show fully reversible capacity for >20 cycles, reaching capacities of 16.1, 15.6, and 14.0 mmol g(-1), respectively, at 273 K and 1 bar. Under the same conditions, MFM-300(V-IV) exhibits the highest uptake among this series of MOFs of 17.3 mmol g(-1). In situ neutron powder diffraction, single-crystal X-ray diffraction, and electron paramagnetic resonance spectroscopy confirm that the redox-active V center enables host-guest charge transfer, with V-IV being reduced to V-III and NH3 being oxidized to hydrazine (N2H4). A combination of in situ inelastic neutron scattering and DFT modeling has revealed the binding dynamics of adsorbed NH3 within these MOFs to afford a comprehensive insight into the application of MOF materials to the adsorption and conversion of NH3.