Tuning fluorocarbon adsorption in new isoreticular porous coordination frameworks for heat transformation applications

Adsorption heat transformation is one of the most energy-efficient technologies, which relies much on the type and performance of the adsorbent-adsorbate pair. Here, we report adsorption behaviors of a typical fluorocarbon R22 (CHClF2) in a new series of isoreticular porous coordination polymers [Zn4O(bpz)(2)(ldc)], in which the typical Zn4O clusters are connected by hydrophobic 3,3',5,5'-tetramethyl-4,4'-bipyrazolate (bpz(2-)) and different linear dicarboxylates (ldc(2-)) to form non-interpenetrated pcu networks with variable pore sizes, shapes, and volumes. Fluorocarbon sorption measurements of these materials revealed high R22 uptakes of 0.73-0.97 g g(-1) (0.62-0.65 g cm(-3)) at 298 K and 1 bar and working capacities of 0.41-0.72 g g(-1) (0.35-0.47 g cm(-3)) between 273 and 313 K at about 0.13, 0.11 and 0.52 bar, respectively, as well as very large diffusion coefficients of 5.1-7.3 x 10(-7) cm(2) s(-1). Noteworthily, the R22 sorption performance can be dramatically improved by subtle modification of the pore size and shape, demonstrating porous coordination polymer-fluorocarbon as a promising adsorbent-adsorbate pair for heat transformation applications.