Plasmonic nanoparticles have sparked wide interest as photo-catalysts and light harvesting antennas for catalysts to drive electrochemical reactions. Plasmonic photo-catalysis can be achieved by extracting hot charge carriers created by light excitation before hot carriers decay. This study demonstrates the role of hot holes in oxidative electrodissolution of gold nanorods in chloride electrolyte. We monitor the plasmon resonance spectroscopically using snapshot hyperspectral imaging with millisecond time resolution, while electrochemically tuning charge carrier density. Light induced hot charge carriers enhance the rate of gold oxidation and subsequent electrodissolution tenfold. Importantly, we find that hot holes generated from interband transitions contribute more to electro-oxidation compared to holes in the sp-band around the Fermi level. We further show that the reaction onset potential cannot be lowered below the chloride adsorption onset potential, demonstrating that electrochemical mediation is required. These results provide new insights into hot hole driven photocatalysis while emphasizing the need for statistical descriptions of electrochemical non-equilibrium processes on innately heterogeneous nanoparticle supports.

Photoelectrodissolution of single plasmonic nanoparticles

2019 Fall National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.