Microbial synthesis of core/shell gold/palladium nanoparticles for applications in green chemistry

We report a novel biochemical method based on the sacrificial hydrogen strategy to synthesize bimetallic gold (Au)–palladium (Pd) nanoparticles (NPs) with a core/shell configuration. The ability of Escherichia coli cells supplied with H2 as electron donor to rapidly precipitate Pd(II) ions from solu...

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Bibliographic Details
Published in:	Journal of the Royal Society interface Vol. 9; no. 72; pp. 1705 - 1712
Main Authors:	Deplanche, Kevin, Merroun, Mohamed L., Casadesus, Merixtell, Tran, Dung T., Mikheenko, Iryna P., Bennett, James A., Zhu, Ju, Jones, Ian P., Attard, Gary A., Wood, J., Selenska-Pobell, Sonja, Macaskie, Lynne E.
Format:	Journal Article
Language:	English
Published:	England The Royal Society 07-07-2012
Subjects:	Benzyl Alcohol - chemistry Bimetallic Catalysts Bioreduction Catalysis Core/shell Escherichia coli Escherichia coli - metabolism Gold Gold - chemistry Gold - metabolism Hydrogen - metabolism Metal Nanoparticles - chemistry Metal Nanoparticles - ultrastructure Oxidation-Reduction Palladium Palladium - chemistry Palladium - metabolism X-Ray Diffraction
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Summary:	We report a novel biochemical method based on the sacrificial hydrogen strategy to synthesize bimetallic gold (Au)–palladium (Pd) nanoparticles (NPs) with a core/shell configuration. The ability of Escherichia coli cells supplied with H2 as electron donor to rapidly precipitate Pd(II) ions from solution is used to promote the reduction of soluble Au(III). Pre-coating cells with Pd(0) (bioPd) dramatically accelerated Au(III) reduction, with the Au(III) reduction rate being dependent upon the initial Pd loading by mass on the cells. Following Au(III) addition, the bioPd–Au(III) mixture rapidly turned purple, indicating the formation of colloidal gold. Mapping of bio-NPs by energy dispersive X-ray microanalysis suggested Au-dense core regions and peripheral Pd but only Au was detected by X-ray diffraction (XRD) analysis. However, surface analysis of cleaned NPs by cyclic voltammetry revealed large Pd surface sites, suggesting, since XRD shows no crystalline Pd component, that layers of Pd atoms surround Au NPs. Characterization of the bimetallic particles using X-ray absorption spectroscopy confirmed the existence of Au-rich core and Pd-rich shell type bimetallic biogenic NPs. These showed comparable catalytic activity to chemical counterparts with respect to the oxidation of benzyl alcohol, in air, and at a low temperature (90°C).
Bibliography:	ArticleID:rsif20120003 ark:/67375/V84-616PFPKW-X istex:F63C0F803C4D0F184DFC0F93756462236B44FA45 Present address: Departamento de Microbiologia, Universidad de Granada, Campus Fuentenueva 18071 Granada, Spain. href:rsif20120003.pdf ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	1742-5689 1742-5662
DOI:	10.1098/rsif.2012.0003