Anchoring LiCl in the Nanopores of Metal-Organic Frameworks for Ultra-High Uptake and Selective Separation of Ammonia.

Ammonia (NH 3 ) is an important chemical raw material and a unique carbon-free fuel with high hydrogen energy density. Thus, NH 3 capture, storage, and desorption are of significant importance. However, high capacity capture, low energy desorption, and selective separation of NH 3 are still challengs so far. Here, we report high-performance hybrid sorbents by anchoring LiCl in the nanopores of MIL-53-(OH) 2 metal-organic frameworks (MOFs). It is found that the optimal composite shows a capture capacity of 33.9 mmol g -1 NH 3 at 1.0 bar and 25 °C, which far exceeds the current record among the reported porous materials. Notably, the excellent capture capacity at low pressure and high temperature makes it possible to selectively capture NH 3 from NH 3 /N 2 , NH 3 /CO 2 , and NH 3 /H 2 O. It is revealed that synergistic action of NH 3 coordination to the highly dispersed Li + in the MOF nanopores and hydrogen bonding of NH 3 with Cl - account for such an excellent capture and selectivity performance.