Bimetallic nanostructures: combining plasmonic and catalytic metals for photocatalysis

ABSTRACT

Light has emerged as a promising new reagent in chemical reactions, especially in enhancing the performance of metal nanoparticle catalysts. Certain metal nanoparticles support localized surface plasmon resonances (LSPRs) which convert incident light to strong electromagnetic fields, hot carriers, or heat for directing and improving chemical reactions. By combining plasmonically active metals with traditionally catalytic metals, bimetallic nanostructures promote simultaneous light conversion and strong molecular adsorption, expanding the library of light-controlled reactions. In this review, we cover three bimetallic geometries: antenna–reactor, core-shell, and alloyed nanoparticle systems. Each geometry hosts its own set of intermetallic interactions which can affect the photocatalytic response. While antenna–reactor systems rely exclusively on optical coupling between the plasmonic and catalytic metal to enhance reactivity, core-shell and alloy architectures introduce electronic interactions in addition to optical effects. These electronic interactions usually dampen the plasmonic response but also offer the potential for enhanced reactivity and product specificity. We review both state-of-the-art bimetallic photocatalysts as well as emerging research opportunities, including leveraging quantum effects, new computational methods to understand and predict photocatalysts, and atomic-scale architecting of materials.

KEYWORDS:

• Bimetallic
• photocatalysis
• local surface plasmon resonance; nanoparticles; hybrid nanostructures

PACS:

• 73.21.-b
• 73.22.-f
• 78.67.-n
• 82.50.Nd`

Acknowledgments

The authors would like to thank John Abendroth, Alan Dai, Alice Lay, and Briley Bourgeois for helpful comments. K.S. was supported by the Gabilan Stanford Graduate Fellowship and the National Science Foundation Graduate Research Fellowship (DGE-1656518). All opinions expressed in this paper are the authors and do not necessarily reflect the policies and views of NSF. M.V. was supported by a postdoctoral fellowship from the TomKat Center for Sustainable Energy at Stanford University. Support from Chi-Chang Kao at SLAC National Accelerator Laboratory is also gratefully acknowledged.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

1. This is also known as the ensemble effect in literature. Here, we have refrained on using the terminology as to not confuse readers with the (nanoparticle) ensemble effects mentioned in the antenna–reactor section.

Additional information

Funding

This work was supported by the National Science Foundation [DGE-1656518]; Stanford Graduate Fellowship – Gabilan; TomKat Center for Sustainable Energy at Stanford University; Chi-Chang Kao at SLAC National Accelerator Laboratory.