Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
Nat Commun. 2014 Jul 9;5:4368. doi: 10.1038/ncomms5368.
Metal-organic frameworks comprise an important class of solid-state materials and have potential for many emerging applications such as energy storage, separation, catalysis and bio-medical. Here we report the adsorption behaviour of a series of fluorocarbon derivatives on a set of microporous and hierarchical mesoporous frameworks. The microporous frameworks show a saturation uptake capacity for dichlorodifluoromethane of >4 mmol g(-1) at a very low relative saturation pressure (P/Po) of 0.02. In contrast, the mesoporous framework shows an exceptionally high uptake capacity reaching >14 mmol g(-1) at P/Po of 0.4. Adsorption affinity in terms of mass loading and isosteric heats of adsorption is found to generally correlate with the polarizability and boiling point of the refrigerant, with dichlorodifluoromethane > chlorodifluoromethane > chlorotrifluoromethane > tetrafluoromethane > methane. These results suggest the possibility of exploiting these sorbents for separation of azeotropic mixtures of fluorocarbons and use in eco-friendly fluorocarbon-based adsorption cooling.
金属有机骨架包含一类重要的固态材料，具有许多新兴应用的潜力，如储能、分离、催化和生物医学。在这里，我们报告了一系列氟碳衍生物在一组微孔和分级介孔骨架上的吸附行为。微孔骨架在非常低的相对饱和压力（P/Po）为 0.02 时，对二氯二氟甲烷的饱和吸附容量>4 mmol g(-1)。相比之下，介孔骨架在 P/Po 为 0.4 时表现出异常高的吸附容量，达到>14 mmol g(-1)。根据质量负载和等吸附热，吸附亲和力通常与制冷剂的极化率和沸点相关，二氯二氟甲烷>氯二氟甲烷>氯三氟甲烷>四氟甲烷>甲烷。这些结果表明，有可能利用这些吸附剂来分离氟碳混合物的共沸混合物，并在环保的氟碳基吸附冷却中使用。
