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.
ABSTRACT
The contrast-matching SANS technique has been utilised to determine inter-pillar distances (and surface texture) in montmorillonite and beidellite pillared smectite clays; they lie in the range 1.40-1.80 nm, reflecting different inter-pillar orderings.
