자료유형  

 학위논문

Control Number  

0016932771

International Standard Book Number  

9798379844158

Dewey Decimal Classification Number  

500

Main Entry-Personal Name  

Yadav, Vamakshi.

Publication, Distribution, etc. (Imprint  

[S.l.] : Purdue University., 2022

Publication, Distribution, etc. (Imprint  

Ann Arbor : ProQuest Dissertations & Theses, 2022

Physical Description  

1 online resource(127 p.)

General Note  

Source: Dissertations Abstracts International, Volume: 85-01, Section: B.

General Note  

Advisor: Li, Christina W.

Dissertation Note  

Thesis (Ph.D.)--Purdue University, 2022.

Restrictions on Access Note  

This item must not be sold to any third party vendors.

Summary, Etc.  

요약Surface functionalization of metallic nanoparticles is an attractive route to tailor the ensemble geometry and redox properties of active sites in heterogeneous catalysts. However, it is challenging to generate well-defined interfaces through conventional impregnation and one-pot colloidal synthesis methods. In this work, we utilize ligand exchange reactions for post synthetic surface modification of colloidal nanoparticles to generate unique core-shell and surface alloy structures. We use halometallate and metal chalcogenide complexes to create surface sites that are active for electrocatalytic hydrogen evolution reaction (HER).We synthesize a self-limiting monolayer of metal chalcogenides on colloidal Au nanoparticles through biphasic ligand exchange reaction between ammonium tetrathiomolybdate (NH4)2MoS4 complex and Au nanoparticles. Through a combination of spectroscopy techniques and computational methods, we show that strong Au-S interactions introduce electronic and geometric distortion to the geometry and bond metrics of MoS4 2- complex. Moreover, proximal MoS4 units adsorbed on the Au surface interlink to form small MoSx oligomers with highly active bridging disulfide sites. Consequently, these core-shell AuMoS4 nanoparticles exhibit significantly higher HER activity than MoS4 2- supported on non-interacting carbon supports under highly acidic electrolyte conditions. Although post catalysis characterization reveals partial hydrolysis of surface adsorbed MoSxspecies, stable HER activity under bulk electrolysis condition indicates that active sites remain persistent.In an effort to extend these ligand exchange reactions to create metal/metal interfaces on other coinage metal nanoparticles such as Ag, we design metal-ligand coordination complexes to mitigate undesired galvanic replacement reactions. By varying the strength and number of coordinating ligands, we fine-tune the redox potential of oxidized noble metal precursors and confine the deposition of noble metals to a few surface layers of the Ag nanoparticles. We utilize organic amine and phosphine ligands to generate Ag AgM core-shell nanoparticles, where M = Pd, Pt, and Au. Surface alloy or pure metal shells of Pd and Pt on Ag nanoparticles generated through this ligand-based strategy exhibited high precious metal atom utilization in electrocatalytic hydrogen evolution reaction.

Subject Added Entry-Topical Term  

Transmission electron microscopy.

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Electrolytes.

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Histograms.

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Electrodes.

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Spectrum analysis.

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Nanoparticles.

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Carbon.

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Adsorption.

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Hydrogen.

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Particle size.

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Energy.

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Graphene.

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Catalysis.

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Geometry.

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Atoms & subatomic particles.

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Analytical chemistry.

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Atomic physics.

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Chemistry.

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Nanotechnology.

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Optics.

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Physics.

Added Entry-Corporate Name  

Purdue University.

Host Item Entry  

Dissertations Abstracts International. 85-01B.

Host Item Entry  

Dissertation Abstract International

Electronic Location and Access  

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Control Number  

joongbu:643768