In this study, two kinds of effective VLD photocatalysts, AgBr-Ag-Bi 2WO6 nanojunction and Zn:In(OH)ySz solid solution nanoplates have been synthesized and characterized. Zn:In(OH) ySz solid solution nanoplates (Synthesis conditions: 45 mmol L-1 thiourea, 26 mmol L-1 SDS, 0.4≤X≤0.7) have high VLD photocatalytic activities on the degradation of Rhodamine B (RhB), which is due to their suitable band gap and potentials of conduction band and valence band as well as their uniform and small diameter sizes (about 10 nm in width and about 15 nm in length). AgBr-Ag-Bi2WO6 nanojunction exhibits excellent VLD photocatalytic performance both on the degradation of Procion Red MX-5B and pentachlorophenol, and on the disinfection of various bacteria including Escherichia coli, Pseudomonas fluorescens and Alteromonas macleodii. Its excellent performance results from the broadened visible-light response and the synergic effect among the three components under the visible light irradiation, namely the vectorial electron transfer of Bi2WO6→Ag→AgBr. / Moreover, a novel and versatile partition setup has been first constructed to investigate the fundamental mechanism of photocatalytic process. The results indicate that the functional reactive species produced by VLD Zn:In(OH) ySz solid solution nanoplates mainly remain on the surface, thus the direct contact between Zn:In(OH)ySz solid solution nanoplates and RhB is a prerequisite for the degradation of RhB during the photocatalytic process. However, the functional reactive species produced by AgBr-Ag-Bi2WO6 nanojunction can diffuse into the bulk, thus the direct contact between the AgBr-Ag-Bi2WO6 nanojunction and bacteria is unnecessary for the photocatalytic disinfection of bacteria. / Recent years, environmental problems related to organic pollutants and pathogenic microorganisms have emerged as a high national and international priority. To address these significant problems, photocatalysis causes increasing interest as a kind of green and energy-saving technology. However, the traditional photocatalyst TiO2 can only be excited by ultraviolet or near-ultraviolet radiation, which merely occupies about 4% of the solar light spectrum. Notably, the visible region covers the largest proportion of the solar spectrum (about 48%). In order to efficiently utilize solar light, the development of visible-light-driven (VLD) photocatalysts with excellent performances has been urged. / Therefore, in this work, the exploration of VLD photocatalyst gives us the opportunities to utilize solar energy to solve the environmental problems and energy crisis, and the investigation of fundamental mechanism provides us more deep understanding for photocatalytic process. / Zhang, Lisha. / Adviser: P. K. Wong. / Source: Dissertation Abstracts International, Volume: 72-04, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 159-171). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.
| Identifer | oai:union.ndltd.org:cuhk.edu.hk/oai:cuhk-dr:cuhk_344537 |
| Date | January 2010 |
| Contributors | Zhang, Lisha., Chinese University of Hong Kong Graduate School. Division of Life Sciences. |
| Source Sets | The Chinese University of Hong Kong |
| Language | English, Chinese |
| Detected Language | English |
| Type | Text, theses |
| Format | electronic resource, microform, microfiche, 1 online resource (xxv, 171 leaves : ill.) |
| Rights | Use of this resource is governed by the terms and conditions of the Creative Commons “Attribution-NonCommercial-NoDerivatives 4.0 International” License (http://creativecommons.org/licenses/by-nc-nd/4.0/) |
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