| In the 21th century, the energy and environmental issues are the great problems and challenges for human, and the concept of using solar energy to solve the global energy and environmental problems has attracted considerable attention. Heterogeneous photocatalysis is a promising technology to solve global energy and environmental issues, since the photocatalyst is materials can transform solar light into chemical energy with high density, and use solar light to photocatalyze poisonous materials, decompose the harmful coniaminations, purify the water, eliminate the air pollution and so on. As well known, the key problem of photocatalysis is photocatalyst. Among various currently studied photocatalysts, titanium oxide has gotten extensive attention due to its high chemical stability, excellent functionality, nontoxicity, and relatively low price. Although titanium oxide photocatalysis has been confirmed as one of the most potential environment treatment technologies, low photocatalytic activity and limited photoresponse region hinder its practical applications. In order to fully utilize sunlight, researchers have devoted to develop visible light activated photocatalysts and have made certain progress, For example, surface modification and doping can make TiO2 response to the visible light. However,there is very few photocatalyst that can decompose toxin pollutants efficiently at present. Hence developing new photocatalysts that is sensitive to visible light has become a hot topic.The perfect visible light activated photocatalysts should meet the following conditions: 1, in order to make full use of solar energy accounted for around 50% of visible light , it should have visible light activity and its absorption spectrum can effectively covers the wavelength of visible light (400 ~ 800nm); 2, in order to stop electron-hole compound so as to make it complete the perfect oxidation reduction reaction and maintain high photocatalytic activity, it should have large capacity of electron-hole, so can effective drive carriers separation of electron-hole; 3, strong oxidation reduction ability; 4, good stability, can steady in the air and water.So, this thesis is mainly for developing new visible light activated photocatalysts with high charge separation efficiency, wide visible light response, fully absorbing sunlight and high photocatalyst efficiency, one-component,two-components visible light activated photocatalysts nanostructure materials were prepared and the photocatalytic performance were studied. This paper was divided into two parts as follows:In the first section,we present a facile self-assembly approach for the production of microcrystalline hexagonal tungsten bronze nanowire bundles via a one-step hydrothermal reaction. These samples were subsequently found to be efficient visible-light photocatalysts. Methylene blue (MB) decomposition was used as a probe reaction to evaluate the photocatalysis of different samples under visible light (λ>420nm) illumination. It was found that the photocatalytic activity of Na-HT nanowire bundles is superior to that of WO3 (commercial WO3, h-WO3) and the photocatalytic properties of Na-HT vary with the Na+ contents. In addition, according to the first-principles calculations based on density functional theory, the results gained in this study are helpful for understanding the intrinsic mechanism of the enhanced photocatalytic activity for Na+ interstitially doped h-WO3 nanocrystals.In the second section,Na-HT loaded with nanoparticule Ag were prepared with a photodeposition method. Methylene blue decomposition was used as a probe reaction to evaluate the photocatalysis of Ag/ Na-HT under visible light illumination, and the influence different factors of photocatalytic activity were also studied, such as pH,light source and the loading capacity of nanoparticule. |
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