Fabrication and Characterization of Nanostructured Materials with High Catalytic Activity

Abstract

In this dissertation, fabrication, characterization, and application of nanostructured material catalysts are discussed from the point of view of physical and materials chemistry. Brief overviews of the chapter 1 and 2 in this dissertation are shown below. In chapter 1, well-defined uniform anatase TiO2 nanotube arrays with the predominant exposure of the highly energetic {001} facets have been prepared via a two-step anodic oxidation process of Ti foil. With the increase of the first-anodization time (up to 11 h) and/or the NH4F concentration, the exposure degree of the {001} facets, as well as the photocatalytic activity, crystallite sizes, and crystallinity, of prepared TiO2 nanotube arrays has been found to increase. Especially, the photocatalytic activity of TiO2 nanotube arrays increases in accordance with increase in the exposure degree of the {001} facets, suggesting that the highly energetic {001} facets enhance the photocatalytic activity of TiO2 nanotube arrays on a large scale. In chapter 2, morphology-controlled Ag/Au nanocomposite have been fabricated facilely via a modified galvanic replacement reaction using Ag nanocubes as sacrificial templates. The morphologies of Ag/Au nanaocomposites have been readily controlled by adjusting the temperature of the galvanic reaction. Among the prepared samples, Ag/Au nanocomposites fabricated at 85 oC show the most efficient catalytic performances as their largest nanocavities are surrounded by the most porous walls.