title: Anomalous Depletion of Pore-Confined Carbon Dioxide upon Cooling below the Bulk Triple Point: An In Situ Neutron Diffraction Study.
abstract: The phase behavior of sorbed CO{2} in an ordered mesoporous silica sample (SBA-15) was studied by neutron diffraction. Surprisingly, upon cooling our sample below the bulk critical point, confined CO{2} molecules neither freeze nor remain liquid as expected, but escape from the pores. The phenomenon has additionally been confirmed gravimetrically. The process is reversible and during heating CO{2} refills the pores, albeit with hysteresis. This depletion was for the first time observed in an ordered mesoporous molecular sieve and provides new insight on the phase behavior of nanoconfined fluids.
authors.affiliation: Institute of Nanoscience and Nanotechnology, NCSR "Demokritos", 15310 Ag. Paraskevi Attikis, Athens, Greece.
authors.forename: K L
authors.initials: KL
authors.lastname: Stefanopoulos
authors.affiliation: Institute of Nanoscience and Nanotechnology, NCSR "Demokritos", 15310 Ag. Paraskevi Attikis, Athens, Greece.
authors.forename: F K
authors.initials: FK
authors.lastname: Katsaros
authors.affiliation: Institute of Nanoscience and Nanotechnology, NCSR "Demokritos", 15310 Ag. Paraskevi Attikis, Athens, Greece.
authors.forename: Th A
authors.initials: TA
authors.lastname: Steriotis
authors.affiliation: Institute of Nanoscience and Nanotechnology, NCSR "Demokritos", 15310 Ag. Paraskevi Attikis, Athens, Greece.
authors.forename: A A
authors.initials: AA
authors.lastname: Sapalidis
authors.affiliation: Quantachrome Instruments, 1900 Corporate Drive, Boynton Beach, Florida, USA.
authors.forename: M
authors.initials: M
authors.lastname: Thommes
authors.affiliation: ISIS Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Oxford, Didcot OX11 0QX, United Kingdom.
authors.forename: D T
authors.initials: DT
authors.lastname: Bowron
authors.affiliation: ISIS Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Oxford, Didcot OX11 0QX, United Kingdom.
authors.forename: T G A
authors.initials: TG
authors.lastname: Youngs