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Binary Au/MWCNT and ternary Au/ZnO/MWCNT nanocomposites: synthesis, characterisation and catalytic performance.
- Source :
-
Chemistry (Weinheim an der Bergstrasse, Germany) [Chemistry] 2010 Feb 15; Vol. 16 (7), pp. 2300-8. - Publication Year :
- 2010
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Abstract
- Gold nanoparticles of 10-24 and 5-8 nm in size were obtained by chemical citrate reduction and UV photoreduction, respectively, on acid-treated multiwalled carbon nanotubes (MWCNTs) and on ZnO/MWCNT composites. The shape and size of the deposited Au nanoparticles were found to be dependent upon the synthetic method used. Single-crystalline, hexagonal gold particles were produced in the case of UV photoreduction on ZnO/MWCNT, whereas spherical Au particles were deposited on MWCNT when the chemical citrate reduction method was used. In the UV photoreduction route, n-doped ZnO serves as the e(-) donor, whereas the solvent is the hole trap. All materials were fully characterised by UV/Vis spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy and BET surface analysis. The catalytic activity of the composites was studied for the selective hydrogenation of alpha,beta-unsaturated carbonyl compound 3,7-dimethyl-2,6-octadienal (citral). The Au/ZnO/MWCNT composite favours the formation of unsaturated alcohols (selectivity=50% at a citral conversion of 20%) due to the presence of single-crystalline, hexagonal gold particles, whereas saturated aldehyde formation is favoured in the case of the Au/MWCNT nanocomposite that contains spherical gold particles.
Details
- Language :
- English
- ISSN :
- 1521-3765
- Volume :
- 16
- Issue :
- 7
- Database :
- MEDLINE
- Journal :
- Chemistry (Weinheim an der Bergstrasse, Germany)
- Publication Type :
- Academic Journal
- Accession number :
- 20029915
- Full Text :
- https://doi.org/10.1002/chem.200901987