Abstract

Successfully combining the catalytic and plasmonic properties of metal nanoparticles would enable significant advances in plasmon-enhanced chemistry, possibly including harvesting light to generate chemical fuels. However, the heavily damped plasmon resonances of many catalytically active metals (e.g., Pt, Pd) prevent this dual functionality in pure nanostructures. The addition of catalytic metals at or close to the surface of efficient plasmonic particles, and the creation of alloys, thus represent enticing opportunities if the resonances can be conserved.

The first part of this talk will discuss the behavior of bimetallic catalytic-plasmonic systems including Au/Pd octopods, Pt-decorated Au prisms, and transition metal-decorated Al nanocrystals. We characterize these structures across length scales with optical spectroscopy and electron tomography, and then show that these plasmonic nanomaterials incorporating catalytically active but heavily damped metals sustain multiple size-dependent LSP Rs and retain their catalytic activity.

The second part of this talk will discuss how electrochemistry can be used to synthesize and manipulate bimetallic nanostructures. First I will discuss using nanoscale electrochemistry to deposit Cu on the surface of Au nanoparticles in a controllable and spatially dependent manner that we can monitor in real time using high throughput hyper spectral imaging. Secondly, I will discuss using partial galvanic replacement of Ag by Au in nanorods to create semi-hollow nanostructures encompassing an aqueous solution. By driving a hydrolysis mediated Ag/Ag+ redox cycle in this trapped nanovolume, we are able to dramatically and reversibly manipulate the internal structure, thereby reshaping the plasmon-modes and introducing a new class of reconfigurable plasmonics.