Date of Graduation

Spring 2015

Degree

Master of Science in Materials Science

Department

Physics, Astronomy and Materials Science

Committee Chair

Robert Mayanovic

Keywords

nanoparticles, Lanthanides, XRD, TEM, XPS, photocatalysis, PL

Subject Categories

Materials Science and Engineering

Abstract

Anatase TiO2 has been shown to be potential applications for photo-remediation of chemical waste as well as for photocatalytic splitting of water. The catalytic properties of TiO2 materials can be modified by doping with lanthanide (Ln) ions. In order to minimize the distortion and/or change of the structure of TiO2 nanoparticles, surface doping of anatase TiO2 nanoparticles (~ 14 nm) with several Ln ions (Nd3+, Gd3+, Eu3+, Yb3+) has been successfully made. X-ray diffraction (XRD) and Raman characterization shows that the anatase phase of treated nanoparticles is well preserved. Scanning electron microscopy (SEM) shows that the majority of the nanoparticles exhibit nanocrystalline shape and transmission electron microscopy (TEM) shows TiO2 core and Ln-TiO2 shell structure having a uniform phase consistent with the anatase atomic-scale structure. Energy Dispersive X-ray (EDX) spectroscopy confirms the presence of Ln ions within the Ln-TiO2 nanoparticles. Temperature dependent in situ optical measurements show an increase in photoluminescence (PL) in forming gas (5% H2 + 95% Ar) at 520 °;C which is attributed to nanoparticle modification (i.e. core-shell structure) induced by doping and use of the hydrothermal treatment. The increase in the distinguishable features in the PL spectrum at low and high (near IR) wavelength regions are attributed to various contributions from oxygen-vacancies and trapped electrons, respectively. Furthermore, X-ray Photoelectron Spectroscopy (XPS) has been performed to observe the shift in the local chemical states due to Ln incorporation into the anatase TiO2 structure.

Copyright

© Rezwanur Rahman

Open Access

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