In-situ crystallization of CALF-20 nanoparticles in poly(acrylate) with enhanced CO2 capture capability toward high-humidity flue gases

CALF-20 nanocrystals uniformly anchored on the macroporous surface of poly(acrylate) via in situ crystallization technique, forming a carbophilic/hydrophobic functional composite. Scalability supports the successful kilogram-scale production. The composite extends the application scope of CALF-20 from cement kilns to post-combustion high-humidity flue gases due to the rapid CO2 adsorption kinetic and the blocking effect of the hydrophobic shell on water. [Display omitted] •Nano-ZnC2O4 seeds in the confined space induced inhomogeneous nucleation.•CALF-20 nanocrystals provided high adsorption efficiency and low diffusion barrier.•The composite yielded 2.2 times CO2/N2 dynamic selectivity than that of the powder.•The composite retained 97.1% dry CO2 uptake at high-humidity simulated flue gas. To extend the application range of Calgary framework-20 (CALF-20, Zn2(1,2,4-triazolate)2(oxalate)), an in-situ crystallization method was used to synthesize spherical CALF-20@poly(acrylate) composite. Owing to the inhomogeneous nucleation induced by nano-ZnC2O4 in poly(acrylate), the size of CALF-20 was reduced to 100–200 nm, forming a carbophilic/hydrophobic functional composite with a macroporous/microporous coupling structure. Compared with the original powder, the adsorption efficiency of the CALF-20 nanocrystals in poly(acrylate) improved by 32 %. In a penetration experiment (10 vol% CO2/90 vol% N2 and 90 % relative humidity), the composite retained 97.1 % of its dry CO2 uptake capacity. The dynamic selectivity of CO2/N2 reached 77.5, which was 2.2 times higher than that of the CALF-20 powder. These results demonstrate that CALF-20@poly(acrylate) can be applied to high-humidity flue gases.