High Ammonia Adsorption in MFM-300 Materials: Dynamics and Charge Transfer in Host–Guest Binding

Ammonia (NH3) is a promising energy resource owing to its high hydrogen density. However, widespread application restricted by the lack of efficient and corrosion-resistant storage materials. Here, we report NH3 adsorption in series robust metal–organic framework (MOF) materials, MFM-300(M) (M = Fe, V, Cr, In). VIII, Cr) show fully reversible capacity for >20 cycles, reaching capacities 16.1, 15.6, 14.0 mmol g–1, respectively, at 273 K 1 bar. Under same conditions, MFM-300(VIV) exhibits highest uptake among this MOFs 17.3 g–1. In situ neutron powder diffraction, single-crystal X-ray electron paramagnetic resonance spectroscopy confirm that redox-active V center enables host–guest charge transfer, with VIV being reduced VIII oxidized hydrazine (N2H4). A combination inelastic scattering DFT modeling has revealed binding dynamics adsorbed within these afford comprehensive insight into MOF materials conversion NH3.