The development of advanced CO2 capture technologies requires innovative materials and solvent systems tailored for diverse industrial conditions. This work bridges two groundbreaking approaches: (1) the design of Type II porous liquids (PLs) for high-pressure CO2 separation and (2) the modification of these materials into water-lean amine systems for efficient flue gas treatment.
In the first study, we engineered low-viscosity Type II PLs by dissolving porous organic cages (CC13, CC19) in bulky solvents (2'-HAP, 2-IPP, 2-CP). These PLs exhibited non-additive CO2 uptake, surpassing the sum of individual components, with 10 wt.% 2'-HAP-CC13 showing 0.51 mmol CO2/g PL excess absorption at 5.3 bar. Molecular simulations revealed that cage surfaces introduced additional sorption sites, amplifying CO2 solubility in the liquid phase.
Building on these insights, we developed a novel liquid-phase absorption system combining chemisorption with tailored solvents for post-combustion flue gas (4.5–25% CO2). This system achieved a remarkable CO2 uptake of >0.8 mol CO2/mol amine, breaking the 0.5 stoichiometry barrier of conventional water-lean amines. Dynamic breakthrough experiments confirmed stable cyclic operation, high working capacity, and reduced regeneration energy.
Together, these advances highlight the versatility of molecular design in CO2 capture, from high-pressure non-additive uptake to cooperative solvent-amine interactions for industrial flue gas applications. The findings pave the way for scalable solutions in blue hydrogen production and carbon-intensive industries.