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Titolo:
SANS investigation of nitrogen sorption in porous silica
Autore:
Smarsly, B; Goltner, C; Antonietti, M; Ruland, W; Hoinkis, E;
Indirizzi:
Max Planck Inst Colloids & Interfaces, D-14424 Potsdam, Germany Max PlanckInst Colloids & Interfaces Potsdam Germany D-14424 m, Germany Univ Marburg, Fachbereich Chem, D-35032 Marburg, Germany Univ Marburg Marburg Germany D-35032 eich Chem, D-35032 Marburg, Germany Hahn Meitner Inst Kernforsch Berlin GmbH, D-14091 Berlin, Germany Hahn Meitner Inst Kernforsch Berlin GmbH Berlin Germany D-14091 Germany
Titolo Testata:
JOURNAL OF PHYSICAL CHEMISTRY B
fascicolo: 4, volume: 105, anno: 2001,
pagine: 831 - 840
SICI:
1520-6106(20010201)105:4<831:SIONSI>2.0.ZU;2-L
Fonte:
ISI
Lingua:
ENG
Soggetto:
ANGLE NEUTRON-SCATTERING; MESOPOROUS MOLECULAR-SIEVES; HARD-SPHERE FLUID; NANOPOROUS SILICAS; BENZENE ADSORPTION; D-DIMENSIONS; GLASS; SYSTEMS; PORES; WATER;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
60
Recensione:
Indirizzi per estratti:
Indirizzo: Smarsly, B Max Planck Inst Colloids & Interfaces, Res Campus Golm, D-14424Potsdam, Germany Max Planck Inst Colloids & Interfaces Res Campus Golm Potsdam Germany D-14424
Citazione:
B. Smarsly et al., "SANS investigation of nitrogen sorption in porous silica", J PHYS CH B, 105(4), 2001, pp. 831-840

Abstract

The mechanism of nitrogen sorption in porous silica was investigated by small-angle neutron scattering (SANS). Two samples of porous silica were studied containing mesopores (pore sizes 5.5 and 9.5 nm, respectively) and additional micropores of irregular shape and statistical distribution. SANS curves were recorded at a temperature of 78 K at various relative pressures pipe during adsorption, The experiment is based on contrast matching between silica and condensed nitrogen with regard to neutron scattering. The sorption process was characterized by the evaluation of the chord-length distributions extracted from SANS data for each pipe. In addition, a general approach was developed to relate the SANS pattern during capillary condensation to the size distribution and the morphology of ordered mesopores. On the basis of these evaluation methods, various uptake mechanisms could be described, which are micropore filling, the formation of nitrogen layers, and capillary condensation. The analysis of the SANS data shows that the mean size of the remaining empty mesopores formally increases, and their size distribution becomes narrower during capillary condensation, which is in agreement with the predictions of the Kelvin equation. Furthermore, our study indicates a significant degree of additional microporosity, the origin of which isdiscussed. For comparison, the experiment and the data evaluation were also applied to a disordered porous silica with a broad pore size distribution. The combination of SANS and nitrogen sorption turned out to be a powerfultechnique to investigate both the mechanisms of sorption and the structureof porous silicas in one experiment.

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Documento generato il 14/07/20 alle ore 12:55:05