Gold Nanohydride Clusters: A New Strategy to Design and Control Uncoordinated Surface Sites as in-situ Catalytic Centers

Dong, Jia

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Year:: 2023
Contributor:: Dong, Jia (creator); Wang, Lai-Sheng (Advisor); Kim, Eunsuk (Reader); Robinson, Jerome (Reader); Brown University. Department of Chemistry (sponsor)
Genre:: theses
Subject:: Catalysts; nanocluster; Chemistry; Gold; Cluster chemistry; Hydrides
Extent:: xxiv, 189 p.

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Abstract:: One of the goals of cluster science is to discover highly stable clusters and use them as building blocks for cluster-assembled materials or models for catalysis. The investigation of gaseous size-selected gold clusters has led to the discoveries of the golden buckyball (Au16) and the golden pyramid (Au20), which possess interesting chemical and physical properties. Our goal is to achieve solution syntheses of ligand-protected pyramidal Au20 and the Au16 cage nanoclusters with uncoordinated surface Au atoms (ucAu) as atomically-defined and in-situ catalytic active centers. Phosphine ligands were thought to be suitable for the synthesis of Au20 to maintain its pyramidal structure. A series of phosphine ligands have been tested to synthesize gold clusters in the Wang lab. During this exploratory work, the Wang group synthesized a Au22 cluster with 8 uncoordinated surface Au atoms, which were found indeed to be in situ catalytic active sites for the CO oxidation reaction. This thesis showed that the as-synthesized Au22 nanocluster was in fact a tetrahydride, but the H atoms were lost during crystallization. This was an unprecedented finding because bulk gold is the most inert metal and does not form gold hydrides even under extreme conditions. Following this study, several new Au nanohydride clusters have been discovered. These gold nanohydride clusters help us understand the interactions of nanogold with hydrogen at the atomic level, and provide the ultimate model systems to elucidate the mechanisms of the remarkable range of chemical transformations catalyzed by gold nanoparticles.
Notes:: Thesis (Ph. D.)--Brown University, 2023

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Citation

Dong, Jia, "Gold Nanohydride Clusters: A New Strategy to Design and Control Uncoordinated Surface Sites as in-situ Catalytic Centers" (2023). Chemistry Theses and Dissertations. Brown Digital Repository. Brown University Library. https://repository.library.brown.edu/studio/item/bdr:spx32rur/

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Theses and Dissertations for the Chemistry department.
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