Evidence and implications of direct charge excitation as the dominant mechanism in plasmon-mediated photocatalysis

Plasmonic metal nanoparticles enhance chemical reactions on their surface when illuminated with light of particular frequencies. It has been shown that these processes are driven by excitation of localized surface plasmon resonance (LSPR). The interaction of LSPR with adsorbate orbitals can lead to the injection of energized charge carriers into the adsorbate, which can result in chemical transformations. The mechanism of the charge injection process (and role of LSPR) is not well understood. Here we shed light on the specifics of this mechanism by coupling optical characterization methods, mainly wavelength-dependent Stokes and anti-Stokes SERS, with kinetic analysis of photocatalytic reactions in an Ag…

• NS
  National Science Foundation

  Awards: 1362120, 1437601
• UD
  U.S. Department of Energy

  Award: FG-02-05ER15686
• CA
  Camille and Henry Dreyfus Foundation
• DO
  Division of Chemical, Bioengineering, Environmental, and Transport Systems

  Awards: FG-02-05ER15686, CBET-1437601
• DO
  Division of Chemistry