Concepts for plasmon-driven chemistry: light-controlled assembly of metal nanoparticles and design of plasmonic reactors

Abstract

Metal nanoparticles are promising catalysts in photo-chemistry, due to their surface plasmon resonances. As part of the fundamental research to bring plasmonic catalysts to applications and devices, plasmonic nanostructures which serve as platforms for the study of their catalytic properties are required. Here we propose an strategy to achieve the assembly of two metal nanoparticles in solution, i.e. a dimer, by virtue of their surface plasmon resonances. We investigated how the surface plasmon resonances of dimers can be used to selectively excite optical and thermal responses, without invoking a significant response in the individual constituent nanoparticles. We find that the size, separation, and material composition are essential parameters to tune the selectivity of the dimer resonances.

In addition, we explored how a reactor with plasmon catalysts would look like and what would be its productivity and economic performance compared with a identical reactor operated in the dark, in which the nanoparticles act just as conventional catalysts. We find that owing to an improved selectivity and lower operating temperature, the productivity and economic performance are better in the plasmonic reactor. However, plasmonic reactors require illumination, and by simply using the Beer-Lambert law, we find that such illumination area can be up to several ha (10000 $ \text{m}^2 $) per every $ \text{m}^2 $ of reactor. This allows us to discuss future perspectives in plasmonic catalysts for commercial applications.