Award Date

8-1-2019

Degree Type

Thesis

Degree Name

Master of Science in Engineering (MSE)

Department

Mechanical Engineering

First Committee Member

Jaeyun Moon

Second Committee Member

Kwang Kim

Third Committee Member

Hui Zhao

Fourth Committee Member

JIn Ouk Choi

Number of Pages

75

Abstract

As the world population continues to grow and access to modern industry become increasingly common, humanity finds itself amid an environmental and energy crisis. Natural resources, such as clean water are getting scarce. Currently, the development of high efficiency, green energy sources, and eco-friendly methods for water treatment have become a nonelective task. As a result, photocatalysis, as one of the most promising technologies in utilizing solar energy and pollutant removal, has attracted considerable attention.

However, the practical application of photocatalysis is still elusive because of the difficulty of finding an individual material that can satisfy all the requirements for an excellent photocatalysis. Recently, the artificial heterogeneous z-scheme Ag3PO4/ Bi2MoO6 composite system showed impressive photocatalytic activity by enabling reduction-oxidation potential optimization and excellent charge separation.

Past reports have achieved photocatalytic performance enhancement in single photocatalyst systems by; boosting light absorption efficiency, increased active surface reaction sites, and reduced charge recombination, through surface morphology control and facet engineering. However, photocatalytic performance boost for Ag3PO4/Bi2MoO6 composite through microstructural control remained an unexplored territory. This study aims to boost the photocatalytic performance and study the effect of microstructural variation in Ag3PO4/Bi2MoO6 Z-scheme composite. Three novel Ag3PO4/ Bi2MoO6 composites are made for that purpose.

Bi2MoO6/Ag3PO4 z-scheme composites were synthesized through a facile in-situ and ex-situ chemical method. The crystallinity, morphology, microstructure, and light absorption wavelength range are characterized using, x-ray diffraction (XRD), X-ray photoelectrons spectroscopy (XPS) scanning electron microscopy (SEM), transfer electron microscopy (TEM), energy dispersive spectrometer (EDS) and UV–visible diffuse reflectance spectroscopy (DRS) and electrochemical impedance spectra (EIS). Finally, photocatalytic performance is evaluated by measuring the photo-discoloration of Methylene Blue (MB) under various lighting system.

The synthesized composite demonstrated satisfactory efficiency for practical application, 100 % degradation of MB 1.5 minutes under natural sunlight irradiation is achieved. The photocatalytic performance of as-synthesized materials differed as a result of the microstructural variation. The polyhedron Ag3PO4/Bi2MoO6 recorded excellent photocatalytic activity due to {111} facet engineered surfaces and convenient morphology.

Keywords

Catalysis; composite photocatalyst; Facet engineering; material synthesis; Photoctalysis; polutant removal

Disciplines

Engineering Science and Materials | Environmental Engineering | Materials Science and Engineering | Oil, Gas, and Energy

Language

English

Available for download on Tuesday, August 15, 2023


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