Nanoscale structural characterization of plasmon-driven reactions

Illumination of noble metal nanostructures by electromagnetic radiation induces coherent oscillations of conductive electrons on their surfaces. These coherent oscillations of electrons, also known as localized surface plasmon resonances (LSPR), are the underlying physical cause of the electromagnetic enhancement of Raman scattering from analytes located in a close proximity to the metal surface. This physical phenomenon is broadly known as surface-enhanced Raman scattering (SERS). LSPR can decay via direct interband, phonon-assisted intraband, and geometry-assisted transitions forming hot carriers, highly energetic species that are responsible for a large variety of chemical transformations. This review critically discusses the most recent progress in mechanistic elucidation of hot carrier-driven chemistry and catalytic processes at the nanoscale. The review provides a brief description of tip-enhanced Raman spectroscopy (TERS), modern analytical technique that possesses single-molecule sensitivity and angstrom spatial resolution, showing the advantage of this technique for spatiotemporal characterization of plasmon-driven reactions. The review also discusses experimental and theoretical findings that reported novel plasmon-driven reactivity which can be used to catalyze redox, coupling, elimination and scissoring reactions. Lastly, the review discusses the impact of the most recently reported findings on both plasmonic catalysis and TERS imaging.