High adsorption of ammonia in a titanium-based metal-organic framework

We report the high adsorption of NH₃ in a titanium-based metal-organic framework, MFM-300(Ti), comprising extended [TiO₆]_∞ chains linked by biphenyl-3,3',5,5'-tetracarboxylate ligands. At 273 K and 1 bar, MFM-300(Ti) shows an exceptional NH₃ uptake of 23.4 mmol g^-1 with a record-high packing density of 0.84 g cm^-3. Dynamic breakthrough experiments confirm the excellent uptake and separation of NH₃ at low concentration (1000 ppm). The combination of in situ neutron powder diffraction and spectroscopic studies reveal strong, yet reversible binding interactions of NH₃ to the framework oxygen sites.