Palladium cobalt binary doping of molecular sieving silica membranes

Ballinger, Benjamin, Motuzas, Julius, Smart, Simon and Diniz da Costa, João C. (2014) Palladium cobalt binary doping of molecular sieving silica membranes. Journal of Membrane Science, 451 185-191. doi:10.1016/j.memsci.2013.09.057

Author Ballinger, Benjamin
Motuzas, Julius
Smart, Simon
Diniz da Costa, João C.
Title Palladium cobalt binary doping of molecular sieving silica membranes
Journal name Journal of Membrane Science   Check publisher's open access policy
ISSN 0376-7388
Publication date 2014-02-01
Year available 2013
Sub-type Article (original research)
DOI 10.1016/j.memsci.2013.09.057
Open Access Status
Volume 451
Start page 185
End page 191
Total pages 7
Place of publication Amsterdam, Netherlands
Publisher Elsevier
Collection year 2014
Language eng
Formatted abstract
This work investigates the preparation and performance of palladium cobalt binary doped silica (PdCoSi) membranes. In view that palladium nitrates precipitate under typical silica sol-gel synthesis conditions, membranes were prepared via the acid catalysis of tetraethylorthosilane (TEOS) with ethanol, palladium and cobalt chlorides. The largest H2 fluxes reached 0.6×10-6molm-2s-1Pa-1 at 500°C for H2 permeation for the reduced membranes, whilst the best He/N2 permselectivies of 70 were observed for the oxidised membranes. The redox effect resulted in membranes with different performance as the reduction increased the total pore volumes of xerogels. However, XPS analysis revealed that palladium monoxide preferentially reduced to metal palladium, whilst reduction was not significant for cobalt oxide. Hence, the reduction to metallic palladium tailored molecular sieving domains through the loss of oxygen. As a result, the permeance of the larger molecular gases CO2 and N2 increased, whilst only a small increase was observed for the smaller molecular gas He. Interestingly, the membranes essentially remained as molecular sieves as evidenced by temperature dependent activated transport and high permselectivities. The molecular sieving domains created preferential pathways for CO2 and N2 permeance, though the silica matrix integrity remained generally intact. Hence, binary and multi doping of metal oxides in silica matrices can be used as a strategy to attain further functionalities not previously attained by pure silica or single metal oxide doped silica membranes using TEOS as a precursor.
Keyword Binary doping
Gas separation
Molecular gap
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes Published online 7 October 2013

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Chemical Engineering Publications
Official 2014 Collection
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Citation counts: TR Web of Science Citation Count  Cited 17 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 18 times in Scopus Article | Citations
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