A record ammonia adsorption by calcium chloride confined in covalent organic frameworks.

Ammonia is a vital chemical raw material, but it is also a highly toxic environmenal pollutant. However, its highly efficient uptake and reversible release is a challenge. Herein, we have designed and synthesized a series of hybrid materials for efficient NH 3 capture by confining calcium chloride (CaCl 2 ) in a porous covalent organic framework (COF). A high capture capacity of 26.5 mmol g -1 is obtained at 25 °C and 1 bar, which is the highest value among existing porous materials, and NH 3 can be easily desorbed at 80 °C under vacuum for 2 h. Particularly, the hybrid COF is highly efficient for the absorption of low NH 3 content. Such excellent performance is ascribed to the highly dispersion of CaCl 2 in the pores of the COF, and coordinating interaction of NH 3 to Ca 2+ together with hydrogen bond interaction between NH 3 and Cl - .