Titanium and zinc oxide nanoparticles are proton-coupled electron transfer agents.
Oxidation/reduction reactions at metal oxide surfaces are important to emerging solar energy conversion processes, photocatalysis, and geochemical transformations. Here we show that the usual description of these reactions as electron transfers is incomplete. Reduced TiO(2) and ZnO nanoparticles in solution can transfer an electron and a proton to phenoxyl and nitroxyl radicals, indicating that e(-) and H(+) are coupled in this interfacial reaction. These proton-coupled electron transfer (PCET) reactions are rapid and quantitative. The identification of metal oxide surfaces as PCET reagents has implications for the understanding and development of chemical energy technologies, which will rely on e(-)/H(+) coupling.
Department of Chemistry, University of Washington, Seattle WA 98195, USA.
Joel N
JN
Schrauben
Rebecca
R
Hayoun
Carolyn N
CN
Valdez
Miles
M
Braten
Lila
L
Fridley
James M
JM
Mayer
D004583:Electrons; D005609:Free Radicals / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D053768:Metal Nanoparticles / Q000737:chemistry*; D009589:Nitrogen Oxides / Q000737:chemistry; D010084:Oxidation-Reduction; D010636:Phenols / Q000737:chemistry; D011522:Protons; D013816:Thermodynamics; D014025:Titanium / Q000737:chemistry*; D015034:Zinc Oxide / Q000737:chemistry*
D005609:Free Radicals; D009589:Nitrogen Oxides; D010636:Phenols; D011522:Protons; C009495:titanium dioxide; C042329:phenoxy radical; D014025:Titanium; C039900:nitroxyl; D015034:Zinc Oxide