Exceptional Packing Density of Ammonia in a Dual-Functionalized Metal–Organic Framework
Christopher Marsh, Xue Han, Jiangnan Li, Zhenzhong Lu, Stephen P. Argent, Iván da Silva, Yongqiang Cheng, Luke L. Daemen, Anibal J. Ramirez‐Cuesta, Stephen P. Thompson, Alexander J. Blake, Sihai Yang⧫, Martin Schröder
Abstract
High Resolution Image Download MS PowerPoint Slide We report the reversible adsorption of ammonia (NH 3 ) up to 9.9 mmol g –1 in a robust Al-based metal–organic framework, MFM-303(Al), which is functionalized with free carboxylic acid and hydroxyl groups. The unique pore environment decorated with these acidic sites results in an exceptional packing density of NH 3 at 293 K (0.801 g cm –3 ) comparable to that of solid NH 3 at 193 K (0.817 g cm –3 ). In situ synchrotron X-ray diffraction and inelastic neutron scattering reveal the critical role of free −COOH and −OH groups in immobilizing NH 3 molecules. Breakthrough experiments confirm the excellent performance of MFM-303(Al) for the capture of NH 3 at low concentrations under both dry and wet conditions.