03/21/2025
By Kwok Fan Chow
The Kennedy College of Science, Department of Chemistry, invites you to attend a Ph.D. Dissertation defense by Connor Sullivan titled, “Tunable Synthesis, Optical Properties, and Electrocatalytic Applications and Analysis of Multimetallic Nanoparticles: A Study of Au-Sn Alloys and Hydrogen Evolution Catalysts.”
Location: Olney Hall, Room 518
Date: Wednesday, April 2, 2025
Time: 10 a.m.
Committee Chair:
Professor Michael B. Ross, Department of Chemistry, UMass Lowell
Committee Members:
Professor Kwok-Fan Chow, Department of Chemistry, UMass Lowell
Professor David Ryan, Department of Chemistry, UMass Lowell
Professor Ertan Agar, Department of Mechanical Engineering, UMass Lowell
Abstract:
This study investigates the tunable synthesis of AuSn nanoparticles with localized surface plasmon resonance (LSPR) properties, focusing on size-dependent composition and optical behavior. By varying Au seed sizes (5–30 nm), LSPR tuning from 520 to 460 nm was achieved with increasing Sn content, as confirmed by UV-visible spectroscopy. Structural analysis (XRD, WAXS, EDS, TXRF) revealed controlled alloying and intermetallic phase formation, enabling optical tuning for sensing, imaging and catalysis.
Additionally, the work explores hydrogen evolution reaction (HER) electrocatalysis in brackish and neutral electrolytes, identifying four electrocatalysts with activity and stability comparable or superior to Pt. A 1Ni:1Pt catalyst demonstrated similar overpotential (60 mV) to Pt (50 mV) with enhanced stability. A rapid, scalable synthesis method enables efficient screening of electrocatalysts for HER in non-ideal conditions.
Advanced characterization techniques (XPS, PDF, WAXS) provide insights into surface composition, atomic structure, and phase formation offering a comprehensive understanding of plasmonic and catalytic material properties.
All interested students and faculty members are invited to attend.