Evaluating the Photocatalytic Properties of Gold Nanoparticles via Light-Driven Synthesis

Presenter: Joseph Picozzi

Faculty Sponsor: Joseph S. DuChene

School: UMass Amherst

Research Area: Chemistry and Materials Science

Session: Poster Session 6, 4:15 PM - 5:00 PM, Auditorium, A87

ABSTRACT

The development of alternative energy sources and the ability to recycle common pollutants is of high importance to aid in the sustainable energy transition. Plasmonic nanoparticles exhibit tunable optical properties coupled with versatile catalytic activities that are promising for photocatalysis applications. The catalytic capabilities of plasmonic nanoparticles depend on the photo-generation of hot carriers on the metal surface which can be used to drive various redox reactions. Similarly, the light-driven synthesis of gold (Au) nanoparticles relies on the filling of hot holes via an oxidation reaction while metal precursor reduction is driven by hot electrons. This makes the light-driven growth of Au nanoparticles an ideal system to study the properties of generated hot carriers and their potential applications in catalysis. In this study, we investigate the light-driven synthesis of Au nanoparticles, focusing on how reaction pH and hole scavenger species influences the nanoparticle growth rate. By varying the oxidation potential of hole scavengers using pH and hole scavenger species of differing oxidation potentials we can probe the photo-generated hot holes. We found that increased pH led to faster reaction rates, and the use of benzyl alcohol as a hole scavenger also increased the reaction rate. Conversely, a decrease in pH and the use of a hole scavenger with a more positive oxidation potential resulted in slower reactions. Through this work, we aim to deepen our fundamental understanding of hot carriers in Au nanoparticles and define the range of catalytic reactions suitable for their future application in sustainable energy conversion.

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