Polyoxometalate stabilized gold nanoparticles in polymeric ionic liquid as a catalyst Aeshah Alrubayyi 1,2 , John Errington , Simon Doherty 1 1 Newcastle University, UK, 2 University of Hafr Al Batin, Saudi Arabia Metal nanoparticles (MNPs) are of major interest because of their applications in catalysis and nanoscience, and their synthesis requires stabilisers to prevent nanoparticle aggregation. 1 MNPs can be stabilised by ionic liquids (ILs) and also by polyoxometalates (POMs), which can be used in their reduced forms to reduce metal precursors. In POM-stabilised MNPs (POM@MNP), the versatility of POMs enables reactive metal / metal oxide interfaces to be designed and tuned to provide synergy in new tailored catalysts. POM@MNP hybrids show promise as photocatalysts, and the plasmonic behaviour of MNPs presents exciting opportunities for solar-driven plasmonic catalysis with these systems. In this project, the aqueous and non-aqueous formation of POM@AuNP is being investigated using reduced forms of [PMo 12 O 40 ] 3– . UV-Vis and 31 P NMR spectroscopy were used to investigate the initial reduction of [PMo 12 O 40 ] 3– with N 2 H 4 ·H 2 O and the subsequent synthesis of POM@AuNP from [PMo 12 O 40 ] 7– and HAuCl 4 , in an attempt to monitor the fate of the resulting re-oxidised {PMo 12 } POMs. Peaks for [PMo 12 O 40 ] 5– , [PMo 12 O 40 ] 4– and [PMo 12 O 40 ] 3– are visible with increasing oxidation by Au(III) and an extra peak at full oxidation raises the question of whether POMs at the surface of AuNP can be observed by 31 P NMR. Hybrid catalysts have been prepared by incorporating metal NPs and POMs into polymeric ionic liquids (PILs). 2 MNP@PIL hybrids have been shown to be efficient catalysts for the aqueous reduction of nitrobenzene to N -arylhydroxylamine, azoxybenzene, or aniline and incorporation of [PW 12 O 40 ] 3– into {PW 12 O 40 }-AuNP@PIL switches the selectivity from N -arylhydroxylamine to aniline. This might be ascribed to the synergic creation of Brønsted acid sites in the presence of POM. References 1. L. Luska and A. Moores, ChemCatChem , 2012, 4 , 1534-1546. 2. Doherty, et al., ACS Catal. , 2019, 9 , 4777-4791.
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