Nanoantioxidant-driven plasmon enhanced proton-coupled electron transfer

Nanoscale. 2016 Jan 14;8(2):796-803. doi: 10.1039/c5nr04942c.

Abstract

Proton-coupled electron transfer (PCET) reactions involve the transfer of a proton and an electron and play an important role in a number of chemical and biological processes. Here, we describe a novel phenomenon, plasmon-enhanced PCET, which is manifested using SiO2-coated Ag nanoparticles functionalized with gallic acid (GA), a natural antioxidant molecule that can perform PCET. These GA-functionalized nanoparticles show enhanced plasmonic response at near-IR wavelengths, due to particle agglomeration caused by the GA molecules. Near-IR laser irradiation induces strong local hot-spots on the SiO2-coated Ag nanoparticles, as evidenced by surface enhanced Raman scattering (SERS). This leads to plasmon energy transfer to the grafted GA molecules that lowers the GA-OH bond dissociation enthalpy by at least 2 kcal mol(-1) and therefore facilitates PCET. The nanoparticle-driven plasmon-enhancement of PCET brings together the so far unrelated research domains of nanoplasmonics and electron/proton translocation with significant impact on applications based on interfacial electron/proton transfer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antioxidants / chemistry*
  • Biphenyl Compounds / chemistry
  • Electron Spin Resonance Spectroscopy
  • Electrons
  • Gallic Acid / chemistry
  • Kinetics
  • Lasers
  • Metal Nanoparticles / chemistry
  • Nanotechnology / methods*
  • Optics and Photonics
  • Picrates / chemistry
  • Protons
  • Silicon Dioxide / chemistry
  • Silver / chemistry
  • Spectrophotometry, Infrared
  • Spectrophotometry, Ultraviolet
  • Spectrum Analysis, Raman
  • Thermodynamics
  • X-Ray Diffraction

Substances

  • Antioxidants
  • Biphenyl Compounds
  • Picrates
  • Protons
  • Silver
  • Gallic Acid
  • Silicon Dioxide
  • 1,1-diphenyl-2-picrylhydrazyl