Optical Properties and Reactions of Radiation Induced TiO₂Electrons in Aqueous Colloid Solutions

Abstract

This work involves an experimental study of the optical properties of excess electrons in solvated TiO 2 nanoparticles. The excess electrons were produced by γ irradiation of deaerated 2-propanol solutions containing TiO 2 nanoparticles in acidic pH. The irradiation produced propanol radicals and hydrated electrons, which react with TiO 2 sols and produce the blue color of excess TiO 2 electrons. Results are provided for the maximum loading of electrons on the TiO 2 nanoparticles for both Q-particles and large nanocrystallites, and for the extinction coefficients, which were determined by titration. Discussion of the electron spectra in the light of earlier work is presented. In addition, we find that the high local concentration of electrons enables reduction of H 2 O 2 and ClO 4 - by simultaneous two-electron transfer.