Mesoporous Metal-Organic Frameworks with Exceptionally High Working Capacities for Adsorption Heat Transformation.

Mo, Zong-Wen; Zhou, Hao-Long; Zhou, Dong-Dong; Lin, Rui-Biao; Liao, Pei-Qin; He, Chun-Ting; Zhang, Wei-Xiong; Chen, Xiao-Ming et al. · Adv Mater · 2018

basic_science · Level V

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Abstract

Pore size is one of the most important parameters of adsorbents, and mesoporous materials have received intense attention for large guests. Here, a series of mesoporous coordination polymers underlying a new framework prototype for fast expansion of pore size is reported and the profound effect of pore size on adsorption heat transformation is demonstrated. Three isostructural honeycomb-like frameworks are designed and synthesized by combining ditopic linear metal oxalate chains and triangular tris-pyridine ligands. Changing the ligand bridging length from 5.5 to 8.6 and 9.9 Å gives rise to effective pore diameter from 20 to 33 and 37 Å, surface area from 2096 to 2630 and 2749 m<sup>2</sup> g<sup>-1</sup> , and pore volume from 1.19 to 1.93 and 2.36 cm<sup>3</sup> g<sup>-1</sup> , respectively. By virtue of the unique and tunable isotherm shape of mesopores, exceptionally large working capacity up to 1.19 g g<sup>-1</sup> or 0.38 g cm<sup>-3</sup> for adsorption heat transformation can be achieved using R-134a (1,1,1,2-tetrafluroethane) as a working fluid.