Journal Article

FZJ-2022-03634

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Surfactant functionalised cobalt silica membranes – Gas permeation and thin film positron annihilation lifetime spectroscopy characterisation

Olguin, G. (Corresponding author) ; Yacou, C. ; Motuzas, J. ; Butterling, M. ; Meulenberg, W. A.FZJ* ; Smart, S. ; Diniz da Costa, J. C. (Corresponding author)

2022
Elsevier New York, NY [u.a.]

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Please use a persistent id in citations: http://hdl.handle.net/2128/32068  doi:10.1016/j.memsci.2022.121040

Abstract: This work investigates the use of positron annihilation lifetime spectroscopy (PALS) for the in-situ structural characterisation of silica derived thin film membranes. By using a quantified maximum entropy method, PALS allowed for the measurement of a pore size distribution depth profile. PALS measurements were carried out on a series of silica derived membranes where alumina supports were coated with four layers of cationic HTBA surfactant cobalt silica sols wherein the surfactant/cobalt molar ratio loading varied from 0 to 3. PALS results showed that the coated layers adjacent to the porous alumina substrate were characterised by micropores and broad mesopores, a clear indication that the porosity of the substrate affected the pore size at the substrate and thin film interface. The last coated layer resulted in a high concentration of ultra-micropores (dp < 6 Å). This was attributed to the surface smoothness conferred by three previous coated layers. Higher surfactant loadings resulted in an increase in gas permeation and reduction of He/CO2 permselectivity from 91.5 to 3.8. A strong correlation with R2 up to 0.999 was found between the ultra-micropores in the top layer and gas permselectivity, a clear indication that gas separation is controlled by small pore sizes. In this work, PALS showed to be a powerful tool for the characterisation of the structural features of thin films.

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Contributing Institute(s):

1. Werkstoffsynthese und Herstellungsverfahren (IEK-1)

Research Program(s):

1. 1232 - Power-based Fuels and Chemicals (POF4-123) (POF4-123)

Appears in the scientific report 2022

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Database coverage:
; Clarivate Analytics Master Journal List ; Current Contents - Engineering, Computing and Technology ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; Essential Science Indicators ; IF >= 10 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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