Date of Graduation

Summer 2013

Degree

Master of Science in Materials Science

Department

Physics, Astronomy and Materials Science

Committee Chair

Robert Mayanovic

Keywords

TiO[2] nanoparticles, doping, XPS, Eu, photocatalysis, structure, photoluminescence, hydrothermal treatment, anatase phase

Subject Categories

Materials Science and Engineering

Abstract

Europium has the potential to enhance the photocatalytic properties of TiO2nanomaterials. Changes due to Eu doping in a high temperature (200 – 360 degrees C) hydrothermal environment, were investigated to characterize the optical, vibrational andstructural properties of TiO2 anatase nanoparticles. Characterization (Raman, x-ray diffraction) showed that the anatase phase was preserved after hydrothermal treatment of the nanoparticles. Surface chemical properties of the hydrothermally treated nanoparticles were probed with energy dispersive x-ray spectroscopy (EDS) and x-ray photoelectron spectroscopy (XPS). Changes were observed in the oxygen and titanium XPS peaks, both in location in energy and overall peak shape, as the temperature of the hydrothermal environment changed. In addition, it was inferred from XPS and photoluminescence (PL) spectroscopy that there was healing (i.e., reduction) of the oxygen vacancies on the Eudopednanoparticles subsequent to hydrothermal treatment. The primary peak PL, whichis attributed to defect-related bound excitons, of the Eu surface-doped TiO2 nanoparticles is red-shifted by ~ 50 nm. Thus, these materials appear to be more suitable for the reception of light in the visible range in photocatalytic processes than untreated anatase TiO2 nanoparticles. Due to a decrease in oxygen vacancy number, the photocatalytic efficiency of the Eu-doped may be lower than that of unmodified TiO2 nanoparticles.

Copyright

© Phillip McCart

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