Super-Resolution Mapping of a Chemical Reaction Driven by Plasmonic Near-Fields

Plasmonic nanoparticles have recently emerged as promising photocatalysts for light-driven chemical conversions. The illumination of these particles results in the generation of highly energetic charge carriers, elevated surface temperatures, and enhanced electromagnetic fields around them. Distinguishing between these often-overlapping processes is of paramount importance for the rational design of future plasmonic photocatalysts. However, the study of chemical reactions mediated by plasmonic effects is typically performed at the ensemble level and, therefore, limited by the intrinsic heterogeneity of the catalyst particles. Here, we report an in-situ single particle study of a chemical reaction driven solely by plasmonic near-fields. Using super-resolution fluorescence microscopy, we achieve single turnover temporal resolution and ~30 nm spatial resolution. This sub-particle accuracy permits the construction of a clear correlation between the simulated electric field distribution around individual metal nanoparticles and their super-resolved catalytic activity maps. Our results can easily be extended to systems with more complex electric field distributions, thereby guiding the design of future advanced photoactive materials.