Nanoscale structural characterization of plasmon-driven reactions

Abstract

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.

Tip-Enhanced Raman Analysis of Plasmonic and Photocatalytic Properties of Copper Nanomaterials

“…The yield and selectivity of Al- and Cu-based catalysts can be improved via a detailed understanding of photocatalytic processes at the nanoscale . Tip-enhanced Raman spectroscopy (TERS) is an innovative optical nanoscopy technique that can be used to examine the structure of biological specimens, polymers, and chemical and catalytic processes. − In TERS, plasmonic nanostructures are created by a metal evaporation or an electrochemical etching at the apex of the scanning probe. , If such a probe is positioned above the sample and illuminated by light, LSPRs at its apex will enhance the Raman scattering from analytes located directly under the probe. − The metalized scanning probe is then rastered above the surface of the sample of interest with a simultaneous acquisition of TERS spectra. − Next, the spectra are used to generate a chemical map that reveals the structure and composition of the analyzed specimen with a sub-nanometer spatial resolution. − …”

Gold Nanopolyhedron-Based Superlattice Sheets as Flexible Surface-Enhanced Raman Scattering Sensors for Detection of 4-Aminothiophenol

“…Also, plasmon-driven catalytic reaction of 4-ATP to 4,4′- dimercaptoazobenzene (DMAB) can be clearly identified by the Raman signatures at 1141 cm –1 due to δ­(CH) and 1392, 1438 cm –1 due to ν­( N  N ) . This surface-catalyzed reaction has demonstrated the hot-electron generation on the AuNPHs plasmonic sheet and in turns proves its SERS efficiency. , Strikingly, the characteristic peak of 4-ATP can be even detected when the concentration was reduced to nanomolar scale. Therefore, it was demonstrated that the detection limit of the plasmonic AuNPH nanosheeta can reach to 10 nM.…”

“…54 This surfacecatalyzed reaction has demonstrated the hot-electron generation on the AuNPHs plasmonic sheet and in turns proves its SERS efficiency. 55,56 Strikingly, the characteristic peak of 4-ATP can be even detected when the concentration was reduced to nanomolar scale. Therefore, it was demonstrated that the detection limit of the plasmonic AuNPH nanosheeta can reach to 10 nM.…”

Plasmon-catalysed decarboxylation of dicarboxybipyridine ligands in Ru(ii) complexes chemisorbed on Ag nanoparticles: conditions, proposed mechanism and role of Ag(0) adsorption sites

“…Chemical transformations of various chemical species on the surfaces of plasmonic metal nanostructures (NS) have recently become a subject of focused interest particularly in connection with identification of plasmon-catalyzed reactions and elucidation of their mechanisms. [1][2][3][4][5][6][7][8][9][10][11][12][13] Plasmon catalysis provides challenging possibilities of conversion of light energy into chemical bond energy. [1][2][3][4][5][6][7][8][9][10][11][12][13] Surface-enhanced (resonance) Raman spectroscopy (SERS and SERRS) has been established as the most suitable tool for monitoring reactions of molecular species in hybrid systems with plasmonic NS, such as Ag and Au nanoparticles (NPs).…”