In the last decade, gold nanoparticles (AuNPs) have become in an area of continuous research as a consequence of their attractive physico-chemical properties and vast number of applications in material science, catalysis and biomedicine. The properties of NPs result from their high surface/volume ratio, dispersity, and shape, aspects which can be controlled by the choice of stabilising agents and reaction conditions employed in the synthesis. In this context, polyoxometalates (POMs) have been successfully used as clean reducing agents and electrostatic stabilizing groups in the preparation of metal NPs (MNPs) with novel and interesting properties. POMs exhibit remarkable redox and photochemical properties that can be transferred into the MNPs, modifying the electron density at the metal surface and tuning their catalytic functionality. Taking this into account, we decided to explore the syntesis of new AuNPs stabilized by hybrid POMs based on tungsten oxide units. Specifically, we have used hybrid Keggin and Wells-Dawson POMs containing organic groups (thiols) that can interact covalently with the metal surface, allowing us to form stable multicomponent systems (Figure 1). Herein we report the synthesis of new hybrid materials “AuNPs@Hybrid-POMs” throught different methods (Ligand-exchange and Brust-Schiffrin method) and their application as promising catalysts for selective hydrogenation, oxidation reactions or photochemical processes. In addition, an exhaustive characterization of the new hybrid materials was performed by several techniques, such as TEM, UV, IR and XPS spectroscopy. This study enabled us to investigate the interaction mode, covalent or electrostatic, of the different POMs on the AuNP surface.

Gold nanoparticles stabilized by organic-inorganic hybrid polyoxometalates: Synthesis, surface studies and catalytic applications

255th National Meeting (2018)

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