title: CO2 captured in zeolitic imidazolate frameworks: Raman spectroscopic analysis of uptake and host-guest interactions.
abstract: Zeolitic imidazolate frameworks (ZIFs) exhibit enhanced selectivity and increased CO2 uptake due to the incorporation of functional imidazolate units in their structure as well as their extensive porosity and ring flexibility. In situ Raman investigation of a representative host compound, ZIF-69, in practical CO2 pressure and temperature regimes (0-10 bar and 0-64 °C) correlates well with corresponding macroscopic CO2 sorption data and shows clear clear spectroscopic evidence of CO2 uptake. Significant positive shift of the 159 cm(-1) phenyl bending mode of the benzimidazole moiety indicates weak hydrogen bonding with CO2 in the larger cavities of the ZIF matrix. Raman spectroscopy is shown to be an easy and sensitive tool for quantifying CO2 uptake, identifying weak host-guest interactions and elucidating CO2 sorption mechanism in ZIFs.
authors.affiliation: Institute of Advanced Materials, Physicochemical Processes, Nanotechnology, and Microsystems (IAMPPNM), National Centre for Scientific Research "Demokritos", P.O. BOX 60037, 153 10 Aghia Paraskevi Attikis (Greece).
authors.forename: Athanassios G
authors.initials: AG
authors.lastname: Kontos
authors.forename: Vlassis
authors.initials: V
authors.lastname: Likodimos
authors.forename: Charitomeni M
authors.initials: CM
authors.lastname: Veziri
authors.forename: Evangelos
authors.initials: E
authors.lastname: Kouvelos
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Moustakas
authors.forename: Georgios N
authors.initials: GN
authors.lastname: Karanikolos
authors.forename: George Em
authors.initials: GE
authors.lastname: Romanos
authors.forename: Polycarpos
authors.initials: P
authors.lastname: Falaras
mesh_terms: D000327:Adsorption; D000397:Air Pollution / Q000517:prevention & control; D002245:Carbon Dioxide / Q000737:chemistry*; D057965:Carbon Sequestration; D007093:Imidazoles / Q000737:chemistry*; D016062:Porosity; D011312:Pressure; D013059:Spectrum Analysis, Raman; D013696:Temperature; D017641:Zeolites / Q000737:chemistry*
chemical_list: D007093:Imidazoles; D017641:Zeolites; D002245:Carbon Dioxide
keywords: CO2 selectivity; Raman spectroscopy; Zeolite imidazole framework; carbon dioxide; sorption mechanism