title: Fluorocarbon adsorption in hierarchical porous frameworks.
abstract: 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.
authors.affiliation: Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
authors.forename: Radha Kishan
authors.initials: RK
authors.lastname: Motkuri
authors.affiliation: Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
authors.forename: Harsha V R
authors.initials: HV
authors.lastname: Annapureddy
authors.affiliation: Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
authors.forename: M
authors.initials: M
authors.lastname: Vijaykumar
authors.affiliation: Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
authors.forename: H Todd
authors.initials: HT
authors.lastname: Schaef
authors.affiliation: Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
authors.forename: Paul F
authors.initials: PF
authors.lastname: Martin
authors.affiliation: Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
authors.forename: B Peter
authors.initials: BP
authors.lastname: McGrail
authors.affiliation: Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
authors.forename: Liem X
authors.initials: LX
authors.lastname: Dang
authors.affiliation: Van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
authors.forename: Rajamani
authors.initials: R
authors.lastname: Krishna
authors.affiliation: Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
authors.forename: Praveen K
authors.initials: PK
authors.lastname: Thallapally