Protons are known to modulate the energetics and interfacial redox reactivity of metal oxides, but these effects are not yet understood at an atomic level. We are using organic-capped ZnO and TiO2 nanoparticles in aprotic solutions to explore proton-electron transfers at the oxide/solution interface. The particles can be reduced, either photochemically or chemically. The reduced particles are rapidly oxidized by electron transfer to decamethylferrocenium, and by proton/electron transfer to phenoxyl or nitroxyl radical oxidants. The kinetics of these reactions are being examined both by stopped-flow and by laser-flash transient absorption. For instance, we are examining how the rates are affected by changes in the number of electrons and protons per particle. Protonated particles are more easily and extensively reduced, and the complex interplay of protonation and reduction will be discussed.

Exploring the roles of protons in redox reactions of metal oxide nanoparticles

245th National Meeting (2013)

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