Hybrid Deep Eutectic Solvents with Flexible Hydrogen-Bonded Supramolecular Networks for Highly Efficient Uptake of NH3

Graphical Quick on the uptake : A flexible hydrogen-bonded supramolecular network in hybrid deep eutectic solvents (DESs) enables strong physical solvation of NH 3 to achieve high and reversible NH 3 uptake. The unique hybrid DESs showed superior desorption–regeneration performance as well as superb NH 3 /CO 2 selectivity. Serious environmental concerns have led to a great demand for efficient uptake of NH 3 by solvents. However, traditional aqueous absorbents have many shortcomings and efforts to use ionic liquids have met with limited success. A hybrid deep eutectic solvents (DESs) designed with a flexible hydrogen-bonded supramolecular network exhibits both exceptional NH 3 uptake capacity and superior desorption–regeneration performance, along with superb NH 3 /CO 2 selectivity and environmental merit. Elucidated by molecular dynamic simulations and spectroscopic analysis, the abundant hydrogen-bonding sites in the hybrid DESs bind every atom of the NH 3 molecule and enable strong physical reversible solvation, whereas the multiple interactions among the hybrid components create a flexible hydrogen-bonded supramolecular network and allow for solvent-unbreaking absorption to ensure the full participation of the solvent and process stability. A mass solubility of NH 3 up to 0.13 g g −1 was achieved at 313 K and 101 kPa by the hybrid DES choline chloride/resorcinol/glycerol (1:3:5), which is higher than all reported ionic liquids and ordinary DESs. Moreover, the performance remained the same after ten absorption–desorption cycles and the DESs could be easily regenerated.