Electronic Theses and Dissertations

Identifier

692

Date

2012

Date of Award

7-24-2012

Document Type

Thesis

Degree Name

Master of Science

Major

Physics

Concentration

Materials Science

Committee Chair

Sanjay Raj Mishra

Committee Member

Muhammad Shah Jahan

Committee Member

Lam Yu

Abstract

Due to the spectral limitation of popular photocatalysts (PC) TiO2 and ZnO, there is quest for modification of the existing PC to enhance their photocatalytic performance. It has been demonstrated that the coupled nanostructured semiconductors in the form of nanocomposites (NC) enhance the performance by the mutual charge transfer of carriers between each semiconductor components with compatible chemical and electrical properties. ZnO (Bg: 3.37 eV) n-type semiconductor, is most important PC because of its high photosensitivity and stability. CuO (Bg: 1.85 eV), a p-type semiconductor, can be used in conjunction with ZnO to further improve its photocatalytic activity (PCA). Herein, a p-n junction oxide photocatalyst was synthesized by using a simple ball milling technique. The structural, optical and surface properties of the p-n junction photocatalyst CuO/ZnO were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), UV-Vis spectroscopy, Zetasizer Nano ZS (Malvern). The PCA of the photocatalyst was evaluated by photocatalytic oxidation of Methylene Blue (MB). Our study demonstrates a novel p-n junction oxide photocatalyst CuO (wt. 10%)/ZnO having superior PCA for the degradation of model dye under the illumination of UV-Vis light. The MB solution was degraded by 100% within 15 min by the use of CuO (wt. 10%)/ZnO photocatalyst. The enhanced PCA is anticipated from many micro p-n junction formed between ZnO-CuO upon ball milling, which helps in efficient electron/hole pair charge separation upon excitation.

Comments

Data is provided by the student.

Library Comment

dissertation or thesis originally submitted to the local University of Memphis Electronic Theses & dissertation (ETD) Repository.

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