Fabrication of functional transition metal oxide and hydroxide used as catalysts and battery materials

Date of Completion

January 2010

Keywords

Chemistry, Inorganic|Engineering, Materials Science

Degree

Ph.D.

Abstract

My research is focused on developing metal oxide and hydroxide nanomaterials which can be used as battery materials, organic transformation catalysts, and photocatalysts. This research involves studying ZnO with different morphologies as photocatalysts for phenol degradation, producing CuO as olefin epoxidation catalysts, developing V and Cu incorporated manganese oxides as cathode materials for Li-ion batteries, and fabricating α-nickel hydroxide for Li-air battery materials. ^ The first part includes producing ZnO as a photocatalyst for phenol degradation. The goal of this study is the synthesis of ZnO with different morphologies using the solvothermal method. The influence of solvents has been studied in detail. Their properties and photocatalytic performances have been explored as well. ^ The second part of the research is concerned with developing novel urchin-like CuO as an olefin epoxidation catalyst. The purpose of this study is to develop a new catalyst, CuO, for olefin epoxidation. The copper source and precipitators were optimized, and the possible self-assembly mechanism of the urchin-like morphology was proposed. The catalytic activity of CuO for olefin epoxidation was studied. ^ The third part of this work includes developing V, Cu incorporated manganese oxide (V-Cu-OMS-2) as cathode materials for Li-ion batteries. The purpose of this project is to develop a new material with enhanced battery performance. V and Cu incorporated manganese oxide were developed using hydrothermal methods. Octahedral molecular sieve (OMS) materials show mixed valences of Mn 3+ and Mn4+, which produces novel properties in battery applications. Inexpensive starting materials make OMS materials more promising for commercial applications. How the incorporation of V and Cu affected OMS-2 materials was investigated in terms of their crystal structure, morphologies, and surface areas. The battery performance of the incorporated OMS-2 materials with different loading amounts of V and Cu was also studied. ^ In the fourth part of this research, 3D flower-like α-nickel hydroxide with enhanced electrochemical activity was fabricated using a microwave-assisted hydrothermal method. The focus of this study is the synthesis of α-nickel hydroxide and its application for O2 reduction. The synthetic work focused on the preparation of flower-like α-nickel hydroxide using the microwave-assisted hydrothermal method. The α-nickel hydroxide shows superior electrochemical properties compared to those of the β-form. However, it is difficult to make the α-form, since the structure of α-nickel hydroxide is unstable, and it prefers to transfer to the β-form under basic conditions. In this study, flower-like α-nickel hydroxide was prepared using urea as the precipitating agent. The factors, which affected the formation of flower-like morphologies, have been investigated. The electrochemical activity of as-synthesized α-nickel hydroxide for oxygen reduction in an alkaline media was studied. ^

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