Nanoantioxidant-driven plasmon enhanced proton-coupled electron transfer.
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.
Particle Technology Laboratory, Institute of Process Engineering, Department of Mechanical and Process Engineering, ETH Zurich, Sonneggstrasse 3, CH-8092, Zurich, Switzerland. ideligia@cc.uoi.gr and Drug Formulation & Delivery, Institute of Pharmaceutical Sciences, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 3, CH-8093, Zurich, Switzerland.
Georgios A
GA
Sotiriou
Particle Technology Laboratory, Institute of Process Engineering, Department of Mechanical and Process Engineering, ETH Zurich, Sonneggstrasse 3, CH-8092, Zurich, Switzerland. ideligia@cc.uoi.gr.
Christoph O
CO
Blattmann
Particle Technology Laboratory, Institute of Process Engineering, Department of Mechanical and Process Engineering, ETH Zurich, Sonneggstrasse 3, CH-8092, Zurich, Switzerland. ideligia@cc.uoi.gr and Laboratory of Physical Chemistry and Materials, Department of Physics, University of Ioannina, 45110 Ioannina, Greece.
Yiannis
Y
Deligiannakis
D000975:Antioxidants / Q000737:chemistry*; D001713:Biphenyl Compounds / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy; D004583:Electrons; D005707:Gallic Acid / Q000737:chemistry; D007700:Kinetics; D007834:Lasers; D053768:Metal Nanoparticles / Q000737:chemistry; D036103:Nanotechnology / Q000379:methods*; D055095:Optics and Photonics; D010851:Picrates / Q000737:chemistry; D011522:Protons; D012822:Silicon Dioxide / Q000737:chemistry; D012834:Silver / Q000737:chemistry; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet; D013059:Spectrum Analysis, Raman; D013816:Thermodynamics; D014961:X-Ray Diffraction
D000975:Antioxidants; D001713:Biphenyl Compounds; D010851:Picrates; D011522:Protons; D012834:Silver; D005707:Gallic Acid; D012822:Silicon Dioxide; C004931:1,1-diphenyl-2-picrylhydrazyl