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Ahmad, Ayla. "Synthesis and Evaluation of Photocatalytic Properties of BiOBr for Wastewater Treatment Applications." Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/30301.
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Visible light-driven photocatalysis has shown considerable potential in the area of clean and renewable energy, as well as in wastewater treatment. This thesis describes the synthesis, characterization and applicability of a visible-light active photocatalyst, bismuth oxybromide (BiOBr). The photocatalytic activity of BiOBr was investigated through its preparation via hydrothermal and solvothermal synthesis routes under various conditions. Hydrothermal catalyst was prepared using non template based method while for solvothermal synthesis CTAB was used as a template. Parameters of temperature and time of thermal treatment were optimized for each synthesis method and overall tests for catalyst dosage and recyclability were performed. An overall optimal route leading to high photocatalytic performance was also proposed based on the obtained results. Studies were also conducted to examine the applicability of optimally synthesized BiOBr in drinking water applications by studying catalyst-mediated disinfection of E. coli and degradation of phenol. Favourable results were obtained, confirming the prospective application of BiOBr as a viable photocatalyst for disinfection. Furthermore, the potential of enhancing BiOBr to further improve its performance is described through synthesis of a novel PdCl2/BiOBr based photocatalyst. Overall, the performance of BiOBr under various conditions in this study establishes its potential as a holistic photocatalyst and merits further development.
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Sundararajan, Mayur. "Amorphous Semiconductors: From Photocatalyst to Computer Memory." Ohio University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1490967991624172.
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Nascimento, Ulisses Magalhães. "Preparação, caracterização e testes catalíticos de um fotocatalisador magnético (Fe3O4/TiO2) na degradação de um poluente-modelo: acid blue 9." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/75/75132/tde-23042013-112144/.
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A aplicação de semicondutores no tratamento de água e efluentes líquidos é uma tecnologia de remediação ambiental promissora, em especial para poluentes orgânicos. Entre os vários semicondutores que também são fotocatalisadores, o TiO2 é amplamente usado em aplicações ambientais, por ser inerte biológica e quimicamente, ter elevado potencial de oxidação, baixo custo e estabilidade frente à corrosão. Entretanto, o TiO2 também tem algumas desvantagens, tais como: ele é excitado apenas por luz UV e requer uma operação unitária adicional (por exemplo, filtração ou centrifugação) para o reuso do catalisador. Para contornar estas limitações, usou-se um procedimento simples para a síntese de um fotocatalisador magnético (Fe3O4/TiO2) com alta área superficial específica e atividade catalítica, quando comparado com o TiO2 P25 da Evonik. O fotocatalisador foi sintetizado através de um procedimento em três etapas: (1) Partículas α-Fe2O3 foram obtidas por precipitação de uma solução de FeCl3.6H2O 0.01 mol L-1, que foi submetida a uma hidrólise forçada à 100°C por 48 h; (2) Partículas de α-Fe2O3/TiO2 foram obtidas por heterocoagulação de oxi-hidróxidos de Ti(IV) sobre as partículas de α-Fe2O3, as quais foram calcinada a 500°C por 2 h; e (3) As partículas \"casaca/caroço\" do fotocatalisador foram obtidas por calcinação a 400°C por 1 h sob atmosfera redutora (H2). A atividade fotocatalítica do material sintetizado foi avaliada aplicando-o no descoramento de uma solução do corante Azul Ácido 9 (C.I. 42090). Os efeitos do pH e da concentração de catalisador foram estimados por meio de um planejamento fatorial 22. Foi obtido um fotocatalisador com área superficial específica de 202 m2 g-1, facilmente separável do meio reacional em aproximadamente 2 min com o auxílio de um ímã. O fotocatalisador apresentou absorção em toda a região do visível. A maior remoção de cor (54%) foi obtida com pH 3,0, 1,0 g L-1 de catalisador e 2 horas de reação.<br>The use of semiconductors for treating polluted waters and wastewaters is a promising environmental remediation technology, especially for organic pollutants. Among the several semiconductors that are also photocatalysts, TiO2 is extensively used for environmental application, due to its biological and chemical inertness, high oxidation power, low cost, and stability regarding corrosion. However, TiO2 also has some disadvantages, such as: it is only UV-excited and requires an additional unit operation (e.g. filtration or centrifugation) for reuse purposes. In order to work around those limitations, a simple procedure for synthesizing a magnetic photocatalyst (Fe3O4/TiO2), with high specific surface area and good photocatalytic activity when compared to Evonik\'s TiO2 P25, was used. The photocatalyst was synthesized in a three-step procedure: (1) α-Fe2O3 particles were obtained, by precipitation, from FeCl3.6H2O 0.01 mol L-1, which underwent a forced acid hydrolysis at 100°C for 48 h; (2) α-Fe2O3/TiO2 particles were obtained, by heterocoagulation, of Ti(IV) oxide species on the α-Fe2O3, followed by calcination at 500°C for 2 h; and (3) The core/shell photocatalyst particles were obtained by calcination the α-Fe2O3/TiO2 particles at 400°C for 1 h under reducing atmosphere (H2). The photocatalytic activity of the synthesized material was assessed by the color removal of an Acid Blue 9 (C.I. 42090) dye solution. pH and catalyst dosage effects were estimated by a 22 factorial design. Fe3O4/TiO2 core/shell particles with specific surface area of 202 m2 g-1were obtained. They were easily separated from the reaction medium, in approximately 2 min, with the aid of a magnet. The photocatalyst absorbed radiation throughout the visible spectrum. The greatest color removal (54%) was achieved with pH 3.0, 1.0 g L-1 of photocatalyst, and 2 h of reaction.
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Fan, Ka Ho. "Synthesis and evaluation of macroporous TiO2 composite photocatalyst /." View abstract or full-text, 2006. http://library.ust.hk/cgi/db/thesis.pl?CENG%202006%20FAN.
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Mole, Jonathan Michael. "Titanium dioxide as a photocatalyst in water purification." Thesis, University of Kent, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.309747.
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Montoya, Anthony Tristan. "Synthesis of carbon nitrides and composite photocatalyst materials." Diss., University of Iowa, 2018. https://ir.uiowa.edu/etd/6479.
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This thesis describes the synthesis, characterization and photocatalytic applications of carbon nitride (C3N4) and titanium dioxide (TiO2) materials. C3N4 was prepared from the thermal decomposition of a trichloromelamine (TCM) precursor. Several different reactor designs and decomposition temperatures were used to produce chemically and thermally stable orange powders. These methods included a low temperature glass Schlenk reactor, a high mass scale stainless steel reactor, and decomposition at higher temperatures by the immersion of a Schlenk tube into a furnace. These products share many of the same structural and chemical properties when produced by these different methods compared to products from more common alternate precursors in the literature, determined by infrared spectroscopy (IR), nuclear magnetic resonance spectroscopy (NMR), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and elemental analysis. C3N4 is capable of utilizing light for photocatalysis due to its moderate band gap (Eg), measured to be between 2.2 and 2.5 eV. This enables C3N4 to be used in the photocatalytic degradation of organic dyes and the production of hydrogen via the water-splitting reaction. C3N4 degraded methylene blue dye to less than 10% of its initial concentration in less than an hour of UV light illumination and 60% under filtered visible light in 150 minutes. It also degraded methyl orange dye to below 20% in 70 minutes under UV light and below 60% in 150 minutes under visible light. Using precious metal co-catalysts (Pt, Pd, and Ag) photo-reduced onto the surface of C3N4, hydrogen was produced from a 10% aqueous solution of triethanolamine at rates as high as 260 μmol h-1 g-1.
C3N4 was also modified by mixing the precursor with different salts (NaCl, KBr, KI, KSCN, and NH4SCN) as hard templates. Many of these salts reacted with TCM by exchanging the anion with the chlorine in TCM. The products were mostly prepared using the high temperature Schlenk tube reactor, and resulted in yellow, orange, or tan-brown products with Eg values between 2.2 and 2.7 eV. Each of these products had subtle differences in the IR spectra and elemental composition. The morphology of these C3N4 products appeared to be more porous than unmodified C3N4, and the surface area for some increased by a factor of 4. These products demonstrated increased activity for photocatalytic hydrogen evolution, with the product from TCM-KI reaching a peak rate as high as 1,300 µmol h-1 g-1. C3N4 was coated onto metal oxide supports (SiO2, Al2O3, TiO2, and WO3) with the goal of utilizing enhanced surface area of the support or synergy between two different semiconductors. These products typically required higher temperature synthesis conditions in order to fully form. The compositions of the SiO2 and Al2O3 products were richer in nitrogen and hydrogen compared to unmodified C3N4. The higher temperature reactions with C3N4 and WO3 resulted in the formation of the HxWO3 phase, and an alternate approach of coating WO3 on C3N4 was used. The degradation of methyl orange showed a significant increase in adsorption of dye for the composites with SiO2 and Al2O3, which was not seen with any of the individual components. The composite between C3N4 and TiO2 showed improved activity for hydrogen evolution compared to unmodified C3N4.
The surface of TiO2 was modified by the reductive photodeposition of several first row transition metals (Mn, Fe, Co, Ni, and Cu). This process resulted in the slight color change of the white powder to shades of light yellow, blue or grey. Bulk elemental analysis showed that these products contained between 0.04-0.6 at% of the added metal, which was lower than the targeted deposit amount. The Cu modified TiO2 had the largest enhancement of photocatalytic hydrogen evolution activity with a rate of 8,500 µmol h-1 g-1, a factor of 17 higher than unmodified TiO2.
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Kashiwaya, Shun. "Science de surface et propriétés chimiques d'hétérostructures NiO/TiO2 monocristallin." Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0241/document.
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Les photocatalyseurs à base de TiO2 ont été l’objet d’une grande attention comme une méthode durable de purification de l’air ou de l’eau, et de production d’hydrogène par décomposition de l’eau. Une stratégie avantageuse consiste à développer des héterostructures par couplage avec un autre oxyde métallique former une jonction de type Schottky ou avec un autre oxyde métallique pour créer une jonction p-n à l’interface de manière à prévenir les recombinaisons via une séparation de charge « vectorielle » à ces jonctions. De plus, les facettes cristallines jouent un rôle crucial dans le piégeage des porteurs de charge et, donc,dans les réactions rédox photoactivées. Ainsi, le dépôt sélectif de métal ou d’oxyde métallique sur des facettes spécifiques de nanocristaux de TiO2 devrait augmenter l’activité photocatalytique par l’amélioration de la séparation des charges. Dans ce travail, nous avons combiné l’emploi du cocatalyseur de type p NiO pour former des jonctions p-n avec son dépôt sélectif sur des nanocristaux de TiO2 anatase exposant des facettes bien définies. Par ailleurs, des expériences modèles de physique de surface ont été menées pour étudier les propriétés électroniques de ces hétérojonctions<br>TiO2 photocatalysts have attracted attention as a sustainable method for water/air purification and hydrogen production by water splitting. An advantageous strategy is the development of heterostructures by coupling metal oxides to create a p-n junction at their interface in order to prevent there combination by vectorial charge carrier separation at these energy junctions. In addition, crystal facets play a decisive role in the trapping of charge carriers and thus photocatalytic redox reactions. Thus, selective deposition of metal or metal oxides onto specific facets would enhance the photocatalytic activity by improving charge separation. In this work, we have combined the usage of p-type NiO co-catalyst to form p-n junction with its selective deposition onto the specific facet of oriented TiO2nanocrystal photocatalysts. Furthermore, the physical model experiments have been performed to investigate the electronic properties of these heterojunctions
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Yamamoto, Akira. "Studies on Low-temperature De-NoX System over TiO2-based Photocatalysts." 京都大学 (Kyoto University), 2015. http://hdl.handle.net/2433/200501.
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Zhang, Xingmo. "Synthesis, characterization and photocatalyst application of CH3NH3PbBr3 single crystals." Thesis, The University of Sydney, 2020. https://hdl.handle.net/2123/22427.
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Organic-inorganic hybrid perovskites, which combine the advantages of superior optoelectronic properties and solution-processed manufacturing, have emerged as the new class of revolutionary materials with great potential for various practical applications. Encouraged by the longer carrier diffusion length, higher carrier mobility and better optoelectronic properties than their polycrystalline counterparts, increasing research effort has been focused on the preparation and optimization of perovskite single crystals using various solution-synthesis techniques for controlling the morphology and promoting their wide optoelectronic applications. In this regard, further clarifying the microstructure as well as charge carrier transporting behaviors and loss mechanisms within perovskite single crystals will be greatly rewarding, which would further guide to further improve the relevant device performance. Moreover, it would be also of great significance to broaden the device applications of single crystals, considering the excellent optoelectronic properties and their related stability nature and facile processing. In the first work, I synthesized methylammonium lead bromide CH3NH3PbBr3 thin single crystals on Fluorine-doped tin oxide glass (FTO) substrates and Si/SiO2 substrates and characterized their morphology and phase purity, and I found that there are solution residuals on the surfaces and around the single crystals. I further characterized the microstructure and elemental composition, and the charge transport properties of the perovskite thin single-crystals. I found there were two kinds of solution residuals: small perovskite crystals or the mixture of perovskite and PbBr2, which was difficult to be removed and would hinder charge transportation of single-crystalline devices. Hydrogen (H2) production using suitable semiconductors through the photocatalytic water splitting process is a much sought-after technology to reduce greenhouse gases and to further contribute to clean solar hydrogen energy production. To date, it is still a big challenge to find stable semiconductor photocatalysts responding to wide-ranged light illumination. Recently, lead halide perovskites have emerged as promising candidates for the high-performance photocatalysts beyond various other optoelectronic devices owing to their excellent optoelectronic properties. However, most of the previous works on perovskite photocatalysts employed the form of polycrystalline thin films, which still suffer from instability due to water and inherent performance. In my second work, we synthesized the high-quality CH¬3NH3PbBr3 single crystals by the inversed-temperature crystallization method and investigated their performance as a photocathode for water splitting with a simple device structure. An optimized perovskite crystal exhibits a good water-splitting photocurrent density of 0.51 mA cm-2 at 0 V vs. Reversible Hydrogen Electrode (RHE) under the white light illumination. Such devices showed improved stability with no obvious decrease over 600 s. Our work highlights the potential of hybrid perovskite single crystals as photocathodes for photocatalysis in neutral solution.
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Wang, Zheng. "Studies on the Photocatalytic Conversion of CO2 in and by H2O over Heterogeneous Photocatalysts." 京都大学 (Kyoto University), 2015. http://hdl.handle.net/2433/199324.
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王, 征. "不均一系光触媒を用いた水中での二酸化炭素の光還元に関する研究". Kyoto University, 2015. http://hdl.handle.net/2433/199525.
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Huang, Zeai. "Studies on Photocatalytic Conversion of Carbon Dioxide in Water over Heterogeneous Catalysts." Kyoto University, 2018. http://hdl.handle.net/2433/232007.
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Duan, Aoshu. "Preparation and Characterization of TiO2-Based Nano Particles and Tests for Their Activities in Meth¬ylene Blue Photodegradation." Thesis, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/31378.
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A two-step hydrothermal method was applied to synthesis Vanadium Sulfide (IV) coupled with commercial P25 on TiO2 nanoparticle (VS4-on-P25). Materials were characterized by scanning electron microscope (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), ultraviolet–visible spectroscopy (UV-Vis), diffuse reflectance UV-Vis spectroscopy and Raman spectroscopy. Photocatalytic activity of this new material was determined by photo-degradation of Methylene blue (MB) under UV irradiation. Experiments show that the VS4-on-P25 exhibits a higher photocatalytic activity than commercial P25 by providing more active site for dye adsorption, and reducing the recombination of charge carriers. Furthermore, the VS4-on-P25 extends its light-absorption spectrum into visible-light range due to its narrower band gap. The highest photocatalytic activity was found with a VS4 loading of 6 wt.%, which outperforms pure P25 by a factor of 2.29 in MB degradation rate.
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Chinungi, Don. "Surface Treatment of Photocatalyst Metal Supports for VOCs Abatement Applications." Thesis, KTH, Skolan för kemivetenskap (CHE), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-188571.
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In this work, the preparation of photocatalysts’ metal support for applications in purification of industrial gas emissions has been studied. The supports normally used in literature are ceramics, but they are not suitable for industrial applications. Stainless steel and aluminium are much more common in full-scale reactors and were therefore chosen in this investigation. Chemical etching, anodisation, electrochemical DC etching and AC etching treatment methods were used to modify the surface morphology of aluminium and stainless steel plates in order to improve the mechanical stability of photocatalyst (TiO2) coating. Two-part epoxysiloxane hybrid (ESH) and sodium silicate adhesives have been evaluated for use as TiO2 binder. Dip and spray coating techniques were employed for preparing TiO2 coatings on blank plates, pretreated plates, ESH and sodium silicate coated plates. Stainless steel electrochemically etched in dilute aqua regia gave the most mechanically stable coating. It was demonstrated that a high microscale surface roughness of the support improves the mechanical stability of TiO2. Additionally, photocatalytic performance of the coating was higher than that coated on ceramic support. The mechanical stability of TiO2 coated on ESH and sodium silicate using dip and spray coating techniques was exceedingly improved. However, Energy Dispersive Spectroscopy (EDS) analysis showed that TiO2 was embedded in the adhesives. Nevertheless, sprinkling of TiO2 powder on sodium silicate presented a very stable coating regardless of high TiO2 loading. It was also shown that coating of sodium silicate on pretreated plates did not a↵ect the mechanical stability of TiO2 coating. A well coated and uniform surface of TiO2 was achieved by spray coating technique.
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Su, Yang. "Copper oxide nano photocatalyst for wastewater purification using visible light." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/277730.
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This thesis presents the synthesis and characterization of copper oxide nano photocatalyst for wastewater purification using visible light. The presented copper oxide nano material can serve as a low-cost and green technology for environmental applications. Uniform cubic, octahedral and rhombic dodecahedral Cu2O nano crystals with a size of 300-600 nm were synthesized using a simple hydrothermal method. The rhombic dodecahedral Cu2O nano crystals are highly active when driven by low-power white LEDs as a light source. In comparison with other reported photocatalysts, the Cu2O nano crystals in this work show a much higher reaction rate and lower electrical energy per order. The reaction rate and photoefficiency are found to be highly correlated with the irradiated photon flux. The surface termination and facet orientation of Cu2O nano particles were accurately tuned by adjusting the amount of hydroxylamine hydrochloride and surfactant. It is found that Cu2O nano particles with Cu-terminated (110) or (111) surfaces show high photocatalytic activity, while other exposed facets show poor reactivity. The density functional theory simulations confirm that the sodium dodecyl sulfate surfactant can lower the surface free energy of Cu-terminated surfaces, increasing the density of exposed Cu atoms at the surfaces, and thus benefiting the photocatalytic activity. It also shows that the poor reactivity of Cu-terminated Cu2O (100) surface is due to the high energy barrier of holes at the surface region. Amorphous CuxO nano flakes with a thickness of 10 to 50 nm were prepared through the dye-assisted transformation of rhombic dodecahedral Cu2O nano crystals under facile hydrothermal condition. The amorphous CuxO nano flake consists of a combination of Cu(I) and Cu(II) with a ratio close to 1:1. It shows enhanced photocatalytic reactivity towards the degradation of methyl orange compared to rhombic dodecahedral Cu2O nano crystals with all active (110):Cu facets. The chemical composition and architecture remain the same after repeating degradation tests. The high surface-to-volume ratio contributes to its better photocatalytic performance while its low surface energy calculated by the density functional theory simulations explains its improved stability. The as-obtained photocatalysts are able to degrade a wide range of aromatic organics including toluene, chlorobenzene and nitrobenzene effectively. We also demonstrate the capability of decontaminating a wide range of aromatic organics in industrial wastewater that comes from an oil company.
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Guo, Xiaochen. "Preparation and Performances of Sensitized Photocatalyst Systems for Solar Cells." Thesis, Curtin University, 2017. http://hdl.handle.net/20.500.11937/59085.
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Dye-sensitized solar cells (DSSCs) are promising photo-voltaic devices for solar energy conversion. The design of DSSCs includes the configuration of efficient anodes, sensitizer and counter electrode. In this thesis, a series of carbon-based nanomaterials (carbon quantum dots, nanodiamonds and their modified forms) have been developed and successfully applied as sensitizers for DSSCs. Moreover, metal-encapsulated carbon nanotubes and nitrogen-doped graphene have also been prepared and demonstrated their potential as counter electrodes for DSSCs.
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De, La Fuente Garcia Elena Luisa. "Visible Light Photocatalyst for Water Purification and Self-Cleaning Coatings." Doctoral thesis, Università degli studi di Bergamo, 2018. http://hdl.handle.net/10446/108456.
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Pollution in water and atmosphere is a growing concern in the current society and demands short-term solutions. Conventional purification techniques like biological treatment, direct oxidation, etc. cannot eliminate low concentrations or some of the so-called emerging pollutants (hormones, detergents, pharmaceuticals, etc.) thus calling for the use of advanced oxidation processes (AOP), namely, techniques in which highly oxidising agents (mostly OH radicals) are produced to degrade organics compound, bacteria and viruses, reaching the complete mineralization or, at least, producing nontoxic by-products. One of these techniques is heterogeneous photocatalysis: redox reactions are developed on the surface of a solid catalyst that is activated by light. Nowadays the more employed and studied photocatalyst is titanium dioxide (TiO2). Its commercial applications are very diverse, including self-cleaning materials (cements, paints), antifogging materials (mirrors, glasses) and water and air purification devices. The operating limits of this effective photocatalyst are in the fact that it needs UV radiation to be activated, due to its relatively wide band gap (3.2 eV). This is a significant problem in economic terms, for high energy costs, in healthy terms, since UV radiation is dangerous for sight and skin, and it is a limit to the use of sunlight, as only 4 % of the solar spectrum that reaches the Earth surface is in the UV range. To overcome this problem, investigations are focused on TiO2 modifications to render it active with visible light (doping with metal and non-metal ions, coupling with other semiconductors, etc) as well as on the use of other semiconductors with narrower band gap.
A ceramic material, lanthanum orthoferrite (LaFeO3), with ionic and electronic semiconductor properties, is synthesized in our laboratory since 2008 and it is studied for its application in the combustion cells. Knowing that it also works as photoconductor under visible light [3], it can be considered a good candidate to be used as visible light photocatalyst. Its effectiveness in the degradation of organic dyes and other molecules has been reported.
After the successful degradation of organic compounds in the slurry tests carried up with the LaFeO3 powders, our group started to develop deposition systems in order to avoid filtration problems, such as loss of catalyst and costs, thus rendering the reuse of the photocatalyst easier to achieve a practical applicability. In the present thesis two deposition methods were studied: the preparation of a photocatalytic paint and the deposition of the catalyst over a ceramic foam by dip-coating process.
In the first part of the work, LaFeO3 was added to a commercial water based paint. This innovative photocatalytic paint has been tested to prove two aspects:
• Its self-cleaning performances, following the degradation of an azo dye under visible light irradiation.
• The paint durability, executing accelerated ageing tests in a climatic chamber, and subsequently verifying visible alterations and possible diminution of its self-cleaning performances.
In the second part, the objective was the application of the material for the wastewater treatment. In collaboration with the Universidad de Las Palmas de Gran Canaria a handy and resistant photocatalytic foam was developed, to avoid the vigorous continuous stirring required to keep powder in slurry and the necessary filtration after the reactions to reuse the photocatalyst. The support chosen was a commercial ceramic inert porous material (foam) and the deposition method was the dip-coating technique.
To apply this coating technique high quantities of catalyst had to be used because it required the preparation of a very concentrate solution. For this reason and for a possible scaling up, the production rate of the photocatalyst in our laboratory had to be increased. The quality of the catalyst had been largely tested for low production rates. Theoretically the results of the synthesis must be the same; however, a complete characterization and determination of photocatalytic performances were carried out on three batches of catalyst prepared on a large scale.
The photocatalytic foam and the different batches in slurry were tested in the degradation of 4-Nitrophenol. A comparison between the slurry test and the fixed bed test is presented.
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Kuo, Hua-Cing, and 郭驊慶. "Preparations and Photocatalysis Properties of CaIn2O4 Photocatalyst." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/04391152074516358424.
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碩士<br>國立東華大學<br>材料科學與工程學系<br>94<br>Abstract
CaIn2O4 semiconductors were synthesized by a solid-state reaction and characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and UV-visible spectrometer. The photocatalytic activity was evaluated by the photodegradation methylene blue under visible light irradiation. Furthermore, Research the CaIn2O4 Photocatalytic property by different Temperature, doped Ni and NiO-loaded three methods, respectively.
The results indicate that the CaIn2O4 have a fine effect by sintering 700oC, MB degradation finished in 40min (TiO2 P-25 finish in 110min). The Ni doped shows wide range of wavelength up to 600 nm and possess high photocatalytic activity, when x=0.5 finished the MB degradation in 60min. furthermore, The NiO-loaded process result a lower MB degradation rate , because of CaIn2O4 decomposed as a result of Ni(NO3)．6H2O.
Keywords: solid-state reaction, Photocatalyst, methylene blue, MB degradation
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Kosco, Jan. "Organic Semiconductor Nanoparticle Photocatalysts for Hydrogen Evolution from Water." Diss., 2019. http://hdl.handle.net/10754/660322.
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Photocatalytic water splitting using solar irradiation has the potential to produce sustainable hydrogen fuel on a large scale. Practical solar energy conversion requires the development of new, stable photocatalysts that operate efficiently under a broad range of visible wavelengths. Organic semiconductors are increasingly being employed as photocatalysts due to their earth abundance, aqueous stability, and optical absorptions that can be tuned to the solar spectrum. However, much remains unknown about the mechanism of organic semiconductor photocatalysis, and significant efficiency improvements need to be made before organic photocatalysts can achieve practical solar energy conversion.
In chapter 2 the effect of residual Pd on hydrogen evolution activity in conjugated polymer photocatalysts was systematically investigated using colloidal poly(9,9- dioctylfluorene-alt-benzothiadiazole) (F8BT) nanoparticles (NPs). Residual Pd, originating from the synthesis of F8BT via Pd catalysed polycondensation polymerisation, was observed in the form of homogenously distributed Pd NPs within the polymer. Residual Pd was essential for any hydrogen evolution to be observed from this polymer, and very low Pd concentrations (<40 ppm) were sufficient to have a significant effect on the hydrogen evolution reaction (HER) rate. The HER rate increased linearly with increasing Pd concentration from <1 ppm to approximately 100 ppm, at which point the rate began to saturate. Transient absorption spectroscopy experiments support these conclusions and suggest that residual Pd mediates electron transfer from the F8BT NPs to protons in the aqueous phase.
Photocatalysts formed from a single organic semiconductor typically suffer from inefficient intrinsic charge generation, which leads to low photocatalytic activities. In chapter 3 we demonstrate that incorporating a heterojunction between a donor polymer and non-fullerene acceptor in organic NPs can result in hydrogen evolution photocatalysts with greatly enhanced photocatalytic activity. Control of the nanomorphology of these NPs was achieved by varying the stabilizing surfactant employed during NP fabrication, converting it from a core-shell structure to an intermixed donor/acceptor blend, and increasing H2 evolution by an order of magnitude. The resulting photocatalysts display an unprecedentedly high H2 evolution rate of over 60,000 µmolh-1g -1 under 350 to 800 nm illumination and external quantum efficiencies over 6% in the region of maximum solar photon flux.
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Huang, Hong-Ting, and 黃宏庭. "The modification of magnetic photocatalyst." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/69199758385026588770.
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碩士<br>國立高雄應用科技大學<br>化學工程系碩士班<br>96<br>The object of this paper will improve the magnetic photocatalyst by CTAB or PVA, because according the journal of magnetic photocatalyst indicate, the non-magnetic free type TiO2 particles could be produced during the process, the separation and recovery of non-magnetic free type TiO2 particles from water are difficult. The researches mainly restrain the non-magnetic free style TiO2 particles produce and also enhance the effect of TiO2 photocatalytic activities. The synthesized sample was characterized by XRD, FTIR, TGA, XRF, BET, SQUID, SEM, TEM. The photocatalytic activity of the synthesized composite particles was tested by photodegradation of Methyl Orange (MO) and Methylene Blue (MB) under UV illumination (250 nm) and compared with that of commerce photocatalyst P-25.
The result shows, the first part, adopt CTAB to become liquid crystal template to improve magnetic photocatalyst, successful restrain the non-magnetic free type TiO2 particle produce and the surface area have obvious increase. The prepared photocatalysts own the excellent photocatalytic activities and magnetic. Repeated cycles of decomposition of methylene blue in aqueous solution were experimentally confirmed. The second part, carbon coating of magnetic photocatalyst was successfully carried out by heating a powder mixture of poly(vinyl alcohol) and TiO2/SiO2/Fe3O4 under N2 gas flow at temperatures above 700 °C. Carbon coating of magnetic photocatalyst was found to give different merits for photoactive performance, quick adsorption of MO and MB into the carbon layer, decomposition of adsorbed MO and MB by TiO2 and prevention of the interaction of TiO2 with binder resin. Repeated cycles of adsorption and decomposition of methylene blue in aqueous solution were experimentally confirmed.
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Wang, Wen-Yuan, and 王文源. "Study of Magnetic Mesoporous Photocatalyst." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/23953368896794890216.
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碩士<br>國立高雄應用科技大學<br>化學工程系碩士班<br>95<br>Recyclable photocatalysts were successfully prepared to solve the problem of hard recovery of the used TiO2 powder. The Fe3O4 nanoparticle was preliminarily prepared by a co-precipitation, and then the core shell material of SiO2/Fe3O4 was synthesized using Fe3O4 nanoparticle as the core. Consequently, the magnetic mesoporous photocatalyst of TiO2/SiO2/Fe3O4 hybrid were successfully prepared by a sol-gel method.
The synthesized products were characterized by X-ray diffraction (XRD), electron spectroscopy for chemical analysis (ESCA), and small angle X-ray scattering system (SAXS). The morphology of synthesized products was observed by scanning electron microscope (SEM) and transmission electron microscope (TEM). The specific surface area was measured with BET instrument. The magnetic properties were detected by superconducting quantum interference device (SQUID). The photo-activity of synthesized products was performance by using methyl orange as a material for photodecomposition analysis, by UV-VIS absorption spectroscopy.
The results showed that the mesoporous photocatalyst of TiO2/SiO2/Fe3O4 hybrid could be easily separated and recycled by the magnetic force. Meanwhile, the photocatalytic activity of those hybrids did not decline markedly after being used second time.
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Chin-Cheng, Hsu. "Synthesis and Characterization of Composite Photocatalyst." 2005. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-1107200517264000.
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Hsu, Chin-Cheng, and 徐金正. "Synthesis and Characterization of Composite Photocatalyst." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/60810718045510534864.
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碩士<br>國立臺灣大學<br>化學工程學研究所<br>93<br>ZnO/ZnO2 composite photocatalysts were synthesized by hydrothermal treatment at 120 ~ 180 ℃ of ZnO2, which in turn was obtained from an aqueous solution of ZnSO4 and H2O2. The composite particles showed morphology of ZnO prismatic crystallites with small ZnO2 granules “fused” at surface. Besides, SrTiO3/TiO2 composite photocatalysts were prepared by sol-gel and incipient wetness impregnation method and proceeded to calcine at high temperature, with TiO2 as the main phase of the composite.
Photocatalytic activity was characterized based on photocatalytic degradation of methyl orange and methylene blue under UV-light (300 nm) illumination, and the maximum activity was both observed for the composite photocatalysts synthesized based on pre-formed main phase, ZnO/ZnO2 and SrTiO3/TiO2. The enhanced activity has been attributed to the presence of the intimate hetero-structure on the surface of composites and the effective way for the separation of excitons. This study also points out a new approach to synthesize a coupled composite photocatalyst containing strongly coupled constituents by phase transformation among the constituents through one or more than one chemical reaction(s).
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Yu, Ching-Tsung, and 余慶聰. "The development of radio-sensitive photocatalyst." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/74278221018460383082.
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Lin, Jian-An, and 林建安. "Development of UV Photocatalyst Air Cleaner." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/5728s9.
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碩士<br>國立虎尾科技大學<br>電子工程系碩士班<br>105<br>This paper mainly talks about a new type photocatalyst material of the air clean device with UV LED and UV CCFL lamp. Through the measurement of UV LED, the temperature is greater than 100℃, so chose the V CCFL lamp instead of the UV Led, reaching about 83%, in the titanium dioxide photocatalyst material experiment is suitable in a new photocatalyst carriers. To match a suitable fan, with 3D industrial graphics software design the main body of the clean device, combined with 3D printing technology to complete the air cleaner.
The follow-up through a series of elimination rate experiments include: The diameter size of Photocatalyst glass beads, UV CCFL tube spacing adjustment, the number of lamps, with a common filter and so on. The results showed that the best elimination rate of formaldehyde, total volatile organic compounds and fine suspension particles was HCHO: 98%, TVOC: 98%, PM2.5: 92%.
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Morais, Daniela Filipa Sousa. "Advances in bromate reduction by heterogeneous TiO2 photocatalysis: The use of a static mixer as photocatalyst support." Master's thesis, 2018. https://hdl.handle.net/10216/113781.
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Morais, Daniela Filipa Sousa. "Advances in bromate reduction by heterogeneous TiO2 photocatalysis: The use of a static mixer as photocatalyst support." Dissertação, 2018. https://hdl.handle.net/10216/113781.
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Morais, Daniela Filipa Sousa. "Advances in bromate reduction by heterogeneous TiO2 photocatalysis: The use of a static mixer as photocatalyst support." Dissertação, 2002. https://repositorio-aberto.up.pt/handle/10216/113781.
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Cheng-Chun, Peng. "Research on Morphological Control of Nanocrystalline Photocatalyst." 2005. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-1207200520594800.
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林文傑. "Study of Function Test of Nano Photocatalyst." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/46802886799712107716.
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碩士<br>國立臺灣科技大學<br>營建工程系<br>92<br>This study refers old test of Photocatalyst，according to the problems of old test， discuss the character of new material of visible Photocatalyst of future. To find a new test，not only adjudge visible or invisible Photocatalyst，but also study the feasibility on the other item’s test ，and analyze virtue and defect. To appraise the capability that new test displace old’s，for improving accuracy and achieving high expeditious business of test.
Study results show that spectral analysis can achieve high expeditious business and accuracy of primogenial liquid，depollute of film，permanence of film. It can be used to adjudge two types，visible or invisible，this point is quantum leap of test，it can be discern the range of spectral distribution，let us know that the range of spectral distribution of the uprate type. All item’s tests could be conform precision and expeditious.
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Chang, Li-Jen, and 張力壬. "Application of Nano Photocatalyst on Water Purification." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/586e9s.
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碩士<br>國立臺灣科技大學<br>營建工程系<br>94<br>Nano photocatalyst is applied on the proposed water purification device in this research. The device is located on the roof of the building by using the nature power of sun to perform the reaction of nano photocatalyst.
A series of testing is designed in this research to investigate the proposed device which included the parameter of climate, contact area of nano photocatalyst, density of pollutant. The result showed the higher the intensity of sun power, the higher of the capability of purification. Higher contact area induced higher capability of purification from nano photocatalyst. The higher density of pollutant induced the higher purification.
The device is going to apply a pattern for commercial purpose.
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Chien, Yen-tao, and 錢彥滔. "Synthesis and Characterization of TiO2/Fe3O4 photocatalyst." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/7h27q5.
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碩士<br>明道大學<br>材料科學與工程學系碩士班<br>99<br>Our study is to explore how soluble gel ( Sol-Gel ) preparation TiO2/Fe3O4 Photocatalyst complex to destain Indigo in different content Fe3O4 molal ratio in variation situation, like different OD of Indigo and density of seawater at three color light source LED (blue ,white and red). We also used human brine pathogenic bacteria Edwardsiella tarda to measure TiO 2/Fe3O4 antibiotic activities.
The data shows the best destained condition is in 4% Fe3O4 in different OD and 1% Fe3O4 in different density of seawater at blue light source. On marine pathogens Edwardsiella tarda, it has 36.6% sterilization in two hours. However, it still has sterilization activity at blue light.
TiO 2 is non-toxicity and can be recycled by magnet of Fe3O4 . This material is difficult to cause secondary pollution and save some industry prime cost.
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Abdullah, Hairus, and Wang Jia Quan. "Sulfide-based Nano heterostructures for Efficient Photocatalyst." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/x896u7.
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博士<br>國立臺灣科技大學<br>材料科學與工程系<br>104<br>Photocatalysis is one of the prospective techniques to overcome the energy shortage problem and global warming. It has been used widely in many applications such as elimination of gaseous and water pollutants, self-cleaning, antibacterial materials, and water splitting. However, work on enhancing the capability of photocatalysis is ongoing because photocatalysts with high activity and reactive selectivity are required for applications. Some limitations of photocatalyst to obtain high efficiency have been found due to the fast recombination rate of photo carriers. To overcome the limitation, some strategies such as coupling two semiconductors or depositing metal on surface of semiconductors with suitable band edge position can reduce the recombination phenomena. To draw new prospects in this field, metal/p-n nanoheterojunction photocatalyst (Ag-deposited p-type CuBiS2/n-type TiO2 nano composite) and p-n heterojunction between n-type solid solution and p-type semiconductors ((AgIn)xZn2(1-x)S2/Ag2S nanorods) have been successfully synthesized by solution based processes. Their morphologies, structures, and textures were carefully characterized by scanning electron microscope (SEM), high resolution transmission electron microscope (HRTEM), X-ray diffractometry (XRD). On the other hand, the suitable combination of Fourier transform infrared spectroscopy (FTIR), diffuse reflectance spectra (DRS), UV-vis spectrophotometry, X-ray photoelectron spectroscopy (XPS), thermogravimetry analysis (TGA) and Hall measurement were used to characterize and analyze performances of as-designed photocatalyst systems.
There are three parts in this work. The first part deals about the growing of CuBiS2 nanoparticles and thin TiO2 layer on SiO2 sphere to form nano p-n heterojunction and the depositing Ag on its surfaces as electron trapping to reduce the recombination rate between photo carriers. This work is the first report of CuBiS2 semiconductor nanoparticles used as a material for photodegradation. The data showed that the SiO2/TiO2/CuBiS2/Ag composite particles completely degraded 50 mL of 10 ppm AB 1 dye solution in only 5 min under UV light irradiation and 100 mL of 5 ppm AB 1 dye solution in 30 min under visible light irradiation. The good photocatalysis of the composite spheres is attributed to the establishment of a good p−n heterojunction interface between the p-type CuBiS2 and n-type TiO2 semiconductors with the assistance of Ag nanoparticles.
In the second part, the as-prepared photocatalyst of SiO2/TiO2/CuBiS2/Ag composite particles was embedded into thin nylon film to improve its recyclability and to solve the post treatment problems which need high cost and time in the processes. The post treatment is the process of refreshing photocatalyst after being used for removing pollutants. The embedded photocatalyst in thin nylon film (hybrid composite film) was stable and reusable without any post treatment process between the photocatalytic degradation sessions.
The third part of this work was dealing with the heavy metal pollutant such as hexavalent chromium (Cr(VI)) by photocatalytic reduction to precipitate Cr(VI) as Cr(OH)3 with lower toxicity. In the third part, the concepts of p-n heterojunction and solid solution were simultaneously used to utilize high bandgap material such as ZnS and suppress the recombination rate of photo carriers. The photocatalyst was designed by doping Ag and In into ZnS lattice and followed by coupling with p-type Ag2S semiconductor to form Ag2S nanoparticle-decorated (AgIn)xZn2(1-x)S2 nanorod photocatalyst. The results showed only 20 mg of the as-prepared nanocomposites could reduce 100 mL of 10 ppm potassium dichromate by almost 100% in less than 90 min without adding any hole scavenger agents and pH adjustment (pH = 7). The good photocatalytic reduction was related to the narrower bandgap of (AgIn)xZn2(1−x)S2 solid solution because of the hybridized orbitals of Ag, In, Zn, and S and low recombination rate of photogenerated electron and hole pairs due to the effectiveness of p-type Ag2S and n-type (AgIn)xZn2(1−x)S2 nanoheterojunctions. This work not only gives a contribution to the creation of visible light photocatalysis for wide-bandgap semiconductors, but also extends our technological viewpoints in designing highly efficient metal sulfide photocatalyst.
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Peng, Cheng-Chun, and 彭正君. "Research on Morphological Control of Nanocrystalline Photocatalyst." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/12427626768567478154.
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碩士<br>國立臺灣大學<br>化學工程學研究所<br>93<br>TiO2 crystallites were synthesized by a solution chemistry process consisting of a sol-gel step followed by hydrothermal treatment at 180oC, and the effect of additives, including some commonly used surfactants, organic or inorganic acids and bases, on the morphology of crystallites were investigated. Excess chloride or citrate ions in acidic condition tend to retard the grain growth rate by undue adsorption to the crystallite surfaces, resulting in equidimensionl particles; certain organic acids (formic, acetic and benzoic acid) and surfactants (PVP, CTAB) displayed similar influences on the morphology of synthesized crystallites.
However, the growth rates along different lattice directions tend to differ in some basic conditions, leading to elongated crystallites. With increasing NH3 content from [NH3/Ti] = 0 to 50, TiO2 crystallites were increasingly elongated along <001> to form crystallite having predominantly {110} surface planes. While not significant in methyl orange solution, the surface catalytic activities of the crystallites toward degradation of methyl orange under UV-light (300 nm) illumination was found to increase with increasing {110} plane coverage.
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Hsu, Hsin-Cheng, and 許新城. "Graphene Oxide Based Photocatalyst for CO2 Reduction." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/79201113028210992482.
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博士<br>國立臺灣科技大學<br>材料科學與工程系<br>102<br>Artificial photosynthesis is one of the solutions to solve global warming and mitigate the rising demands of energy consumption. Photocatalytic conversion of carbon dioxide (CO2) to hydrocarbons such as methanol makes possible simultaneous solar energy harvesting and CO2 reduction, resulting in solution for both the energy demands and environmental problems. This work describes a promising photocatalyst based on improved graphene oxides (iGOs), which have high photocatalytic conversion efficiency of CO2 to hydrocarbon fuels.
Improved Hummer’s method has been applied to synthesize the GO based photocatalyst for the enhanced catalytic activity. The photocatalytic CO2 to methanol conversion rate on the pristine improved graphene oxide is 0.172 μmole g-1-cat. h-1 under visible light, which is four-fold higher than the pure TiO2 (P25). On the other hand, we have also synthesized a composite catalyst based on molybdenum disulfide-iGO system.The MoS2 nanosheet decorated improved graphene oxide (iGO) hybrid nanostructures are fabricated by a facial one-step hydrazine-assisted hydrothermal method. The photophysical properties of the synthesized photocatalysts have been investigated by X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), UV-Vis spectrometer, Ultraviolet photoelectron spectroscopy (UPS), cyclic voltammetry (CV), linear sweep voltammetry (LSV) and X-ray photoelectron spectroscopy (XPS). Enhanced visible light-driven activity for the CO2 photoreduction to solar fuel has been achieved. The average apparent CO2 reduction to solar fuel formation rate of MoS2 nanosheet decorated iGO composite is more than 10 times higher than the pristine iGO; or 40 times that of TiO2 (P25). The MoS2 nanosheet decorated iGO composite nanostructures makes an outstanding contribution to the excellent photocatalytic CO2 reduction.
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Wu, Chun-Hsing, and 吳俊星. "ORGANIC POLLUTANT DECOMPOSITION KINETICS WITH TiO2 PHOTOCATALYST." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/06014209843345045029.
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博士<br>大同大學<br>化學工程學系(所)<br>94<br>In order to treat the wastewater effluents from dyeing and finishing industries by an advanced oxidation process, the decomposition kinetics of organic dye by nano fine sol TiO2/UV was systematically studied in two batch slurry reactors. The factors of study include agitation speed, re-circulation flow rate, initial dissolved oxygen concentration, initial hydrogen peroxide concentration, initial dye concentration, reaction temperature, TiO2 dosage and UV light intensity. By using the network reduction technique, two general rate equations have been developed from considering the reaction mechanism in literature and that revised for the experiment conditions used in this study. The rate equations were obtained from systematically using the network reduction technique to avoid the need of more restrictive assumptions commonly used such as rate-determining step or equilibrium steps. After discriminating the two rival rate equations by data analysis, the rate equation derived from the revised reaction mechanism was found to better explain the effect of TiO2 suspension concentration on the reaction rate of methylene blue. Another rate equation was also developed for the same revised mechanism in the presence of H2O2. The resulting rate equations developed for methylene blue are applicable to wider range of reaction conditions and even for other organic compounds.
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Wang, Hui-Tsung, and 王惠宗. "The antimicrobial activity of TiO2 nano-photocatalyst." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/19202991189337013306.
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碩士<br>國立臺灣海洋大學<br>食品科學系<br>94<br>The types of nano-photocatalyst, TiO2 (OPT, 30 nm) and Platinum modified TiO2 (SONANO, 35 nm) were used. Thirteen commonly found pathogen including 6 G(+) bacteria and 7 G(-) bacteria, and 3 fungal species were used to the tested microorganisms. The aim of this study was to investigate the antimicrobial activity of OPT and SONANO with UV and fluorescent lamp illumination. The production of reactive oxygen species from OPT and SONANO, and the effects of some factors including temperature, dissolved oxygen, pH, NaCl and bacterial ages on the antimicrobial activity of these two photocatalysts were also studied.
The degradation rates of methylene blue for SONANO by UV (366 nm) and fluorescent lamp (13 W) for 10 hours were 57.73% and 36.41%. Respectively, the degradation rates for OPT were 37.36% and 9.00%. The following conductions were set out to obtain higher antimicrobial activity: cell suspension with a density of 103 cfu / mL, and 0.2 cm in depth were added with 0.01% OPT or SONANO, and illuminated by UV or fluorescent lamp for 2 hours, which was 10 cm above the surface of cell suspension. Except Lactobacillus acidophilus and Listeria monocytogenes, both of which were more resistant to OPT and SONANO, the survival ratio of 11 stains of the tested bacteria in OPT and SONANO by UV illumination were 12.31% ~ 33.86% and 16.82% ~ 59.71%, respectively. The survival ratio of 3 fungal species for OPT and SONANO by UV illumination were 16.22% ~ 29.39% and 19.03% ~ 66.96%, respectively. The survival ratio of 11 bacteria and 3 fungal species in SONANO by fluorescent lamp illumination were 4.57% ~ 46.67%, and 40.85% ~ 66.99%, respectively. The OPT had little antimicrobial activity by fluorescent lamp illumination. OPT and SONANO could produce superoxide anions, hydroxyl radicals and H2O2 during irradiation with UV. SONANO produced about 0.4 mg/L H2O2 illuminated by UV or fluorescent lamp for 2 hours, and OPT produced about 0.33 mg/L H2O2 illuminated by UV for 2 hours. The survival ratio for E. coli and S. aureus obtained from 0.3 mg/L pure H2O2 and from OPT/SONANO were similar. Temperature in the range of 5℃ to 45℃ does not affect the antimicrobial activity of OPT. However, the survival ratio of E. coli in SONANO by UV or fluorescent lamp decreases with the increasing temperature from 5℃ to 45℃. Dissolved oxygen (DO) in the range of 4.20 to 29.57 ppm has little effect on the antimicrobial activity of SONANO. SONANO has the highest antimicrobial activity at pH 6.5 ~ pH 7.0; while the pH does not affect OPT. The cell age of E. coli affects to susceptibility to OPT/SONANO, with the cell in late-log phase being most sensitive. The presence of NaCl, bovine serum albumin and glucose decrease the antimicrobial activity of SONANO. However, 500 ppm soybean oil can increase the antimicrobial activity of SONANO. This may be due to the production of malondialdehyde (MDA) from oil oxidation that was promoted by SONANO. The amounts of MDA produced from SONANO with oxygenized soybean oil by UV and fluorescent lamp illumination for 20 min were 3.29 ppm and 2.65 ppm, respectively.
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Chou, Kai-Ping, and 周開平. "Preparation and Application of Ag/TiO2 Photocatalyst." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/74838047681505909881.
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碩士<br>國立中央大學<br>化學工程與材料工程研究所<br>92<br>Many researches on photocatalysis by TiO2 have been investigated for decades after the first report by Fujishma and Honda in 1972. Metal modification has been extensively used to improve the activity of titania. The purpose of this research focused on the decomposition of contaminants in wastewater produced from industrial process. The usage of TiO2 with specific photocatalytic property is a potential way to decompose the pollutants in wastewater. This research emphasized the effect of silver modification and the photocatalytic activity has been tested by decomposition of methylene blue (MB). During pre-test stage, silver modification has shown remarkable performance in deNOx reaction. Ag/TiO2 powders prepared with impregnation method under proper condition could enhance the photocatalytic activity on MB degradation when compared with the bare TiO2. The usage of ethanol as solvent showed the higher activity than those with isopropanol or pure water during preparation. Catalysts prepared with calcinations and without drying showed higher photocatalytic activity than those prepared with calcinations and drying. Pretreatment by UV illumination (at 254 nm) could enhance the photocatalytic activity of Ag/TiO2 catalysts and the color of the catalysts changed. Ag-TiO2 suspension prepared with adding hydrogen peroxide (H2O2) was very active during MB test for both UV and visible light while TiO2 suspension was only active under UV illumination. According to the XRD analysis, silver modification did not change the crystalline phase of the original bare TiO2. In addition, the deposited silver changed from Ag+ or Ag2+ to metallic form (Ag0) after UV illumination. The role of deposited silver metal on titania surface could be explained as either an electrons trapper or enhancement of electrons transfer from catalysts to dissolved molecular oxygen. Negative charging of deposited silver metal results in faster holes transfer from catalysts to adsorbed MB or to water.
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Fu, Szu-Han, and 傅泀翰. "Photocatalytic Destruction of Dichloromethane by Modified Photocatalyst." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/63376462607552241848.
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碩士<br>國立成功大學<br>環境工程學系碩博士班<br>92<br>In this study, we decompose the dichloromethane over The TiO2 and modified-Fe/TiO2 photocatalysts prepared by the sol-gel methods. We found that the photoactivity of the photocatalysts dried at 393 K for 24 hrs decrease with the ratio of Fe/Ti. The efficiency of the photocatalyst dropped significantly while the ratio of Fe/Ti was over 0.5 mol %. After calcining at 723 K for 4 hrs, the photocatalyst Fe/Ti=0.0005 mol% showed the higher photoactivity for the dichloromethane decomposition than that of TiO2.
The nitrogen-containedompound was detected through a FTIR in the case of the uncalcined photocatalyst. On the basis of this result, it was thought that the NO3- may act as the media to partake the photocatalytic reaction. No nitrogen-contained compounds were detected for the calcined photocatalyst in the FTIR patterns. Additionally, a significant amount of Cl2 gas was analyzed by a Cl2-analyzer during the photocatalytic experiment while no water was fed into the influent gases.
From the BET analysis, the surface area of the uncalcined photocatalyst decreased significantly. This may be due to that FeNO3•9H2O occupied the pores in the photocatalyst and cause low conversion. The formation temperatures of the anatase and rutile decreased with the ratio of Fe/Ti through the XRD and TGA analysis.
For the Fe/Ti=5 mol% photocatalysts, Fe2TiO5 may form at a high calcining temperature. After 24 hrs dried at 393K, the UV-Visible analysis indicated that the distinct absorption region was within the visible-wavelength and was attributed to FeNO3•9H2O, which is low/no photoactivity. However, after 4 hrs calcined at 723 K, the Fe/TiO2 photocatalysts resulted in a definite shift in the absorption spectra toward visible light regions.
In this study, we found the photoactivity decreased at high calcining temperatures and the presence of water resulted in decreasing conversion.
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cheng, Lou wei, and 羅偉誠. "Modifying titanium dioxide photocatalyst to fulfill the degradation Modifying titanium dioxide photocatalyst to fulfill the degradation Modifying titanium dioxide photocatalyst to fulfill the degradation of salicylic acid under visible-light." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/25097179523506886839.
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碩士<br>國立暨南國際大學<br>土木工程學系<br>98<br>This study using metal (Fe、Ni) modified TiO2 catalysts nano-photocatalysts were prepared by sol-gel process. This modification results in catalysts with enhanced visible light absorbance in blue light region . The Fe-TiO2 were 0、0.01、0.05、0.1、0.5 wt% respectively. The Ni-TiO2 were 1、5、10、15 wt% respectively.. The calcined at 400℃、500℃、600℃、700℃. Degradation of salicylic acid respectively under three kind of light sources the visible light lamp (400-500 nm), solar light, the daylight lamp. These catalysts were characterized by the use of Brunauer-Emmett-Teller (BET)、X-ray diffraction (XRD )and Field emission Scanning Electron Microscope (FESEM).
The BET surface area test of the catalysts was 90.12 ~103.44 m2/g. The XRD results, the pure and modified TiO2 calcined at 500 ◦C Began to have a small amount of Rutile phase appears at 700 ◦C are in anatase form. Modification of metals did not cause phase transformation.
The Photocatalysis Degradation of salicylic acid test received the following results. Using Ferrum to modify TiO2, the Fe-TiO2 (0.1 wt%) had the greatest photocatalytic activity. Similarly, using Nickel to modify TiO2, the Ni-TiO2 (10 wt%) had the greatest photocatalytic activity. At the best ratio of modified, preparing TiO2 in different sintered temperatures received the TiO2 which had higher photocatalytic activity at the temperature of 400 ℃. Degrade salicylic acid under the three kinds of light sources including visible light, fluorescent light, and solar light. The degradation has the best photocatalytic activity when the solar light as the light source. In the study, informed that the degradation of salicylic acid is first-order linear regression.
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Chen, Chun-Chi, and 陳狀琦. "Application of Nano Photocatalyst on the Air Purification." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/kvxwjh.
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碩士<br>國立臺灣科技大學<br>營建工程系<br>94<br>Nano Photocatalyst is well known as an air purification material, such as formaldehyde and ammonia. A powerful device composed by nano photocatalyst is designed in the research to purify the air. A series of experimental parameters are set up to investigate the function of the device which included contact surface area of nano photocatalyst, concentration of formaldehyde, power of light source, speed of air and media of nano photocatalyst.
The followings are the short description of the result of this research:
1. The higher the contact area of the surface of nano photocatalyst the higher air purification;
2. The higher concentration of formaldehyde the higher air purification;
3. The higher the power of light the higher air purification.
A pattern is successfully applied to apply the result of this research on the real commercial product. The pattern is a fan modified by the proposed device to gain a additional function of air purification.
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Gong, Jia-You, and 貢家宥. "Removing Indoor Ozone by Visible-light driven Photocatalyst." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/eb7k2c.
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Liu, Shan-Zhou, and 劉善州. "Photocatalytic properties of phosphor doped titanium dioxide photocatalyst." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/47818523106137841948.
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碩士<br>國立高雄應用科技大學<br>化學工程與材料工程系<br>97<br>Recently, many efforts have devoted to investigate titanium dioxide, due to it has the advantages of high chemical stability, nontoxicity, and relatively low-price. Because the photocatalytic activity of titanium dioxide is worse, the modification of phosphorus (P) doped titanium dioxide was prepared via the sol-gel method in this study. The photocatalytic activity was measured by the degradation of methylene blue and methyl orange, and expected that could be improved the efficiency of photocatalytic activity after doped phosphorus.
Phosphorus (P) doped TiO2 nanoparticles were characterized by Fourier Transform Infrared Spectrometer (FTIR), Wide Angle X-ray Diffraction (WAXD), Raman Scattering Spectroscopy and Thermo Gravimetric Analysis (TGA). The specific surface area was measured with N2 adsorption/desorption. The morphology of synthesized product was observed by Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM). The photocatalytic activity of synthesized product (P-TiO2) was evaluated by measuring the degradation of methylene blue (MB) and methyl orange (MO) under UV irradiation. The change of MB and MO concentration was measured by Ultraviolet and Visible Spectroscopy (UV-VIS).
The results show that the modification titanium dioxide (P-TiO2) not only retard the phase transformation of anatase to rutile but also improve the thermal stability. The photocatalytic efficiency of the P doped TiO2 nanoparticles were compared with commercial photocatalyst ST01 and P-25 powders under UV illumination (λ=365 nm). P doped TiO2 nanoparticles show superior photacatalytic efficiency than ST01 and P-25. Repeated cycle tests of decomposition methylene blue in aqueous solution still have better photocatalytic activity.
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Wang, Chia-Ching, and 王嘉慶. "Bactericidal effect of TiO2 photocatalyst on E. coli." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/79889434389692422286.
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碩士<br>國立臺灣大學<br>化學工程學研究所<br>92<br>Photocatalysts, once exposed to light source of specific wavelength, can produce electrons and holes, which can react with water and oxygen to generate reactive hydroxyl free radicals and superoxide ions, respectively. Almost all types of organic and inorganic substances can be degraded by using photocatalysis, thus generating bactericidal effect.
� This study investigated the bactericidal effect of commercial P25 TiO2 under different operating conditions, such as various UV light intensities, photocatalyst loadings, hydrogen peroxide concentrations, etc. The photocatalysis effect of commercial ST01 powder and ZnO powder were compared. Moreover, the degradation of methylene blue was taken as an index of the efficiency of photocatalysis. Bactericidal effect and degradation of methylene blue are first order reactions.The photokilling effect on E. coli of lab-made TiO2 powders was compared with commercial powders .
The results indicated that ZnO powders had the highest photocatalysis ability due to efficient photon absorption and small particle size. The best photocatalysis condition occurred at 5 mg/ml photocatalyst loading with illumination of three UV lights and addition of 1 mM hydrogen peroxide.
Among all lab-prepared powders, TiO2 powder which was sintered at 500oC had the highest photocatalysis activity. The powders which was sintered at 500oC and the powder without sintering were more efficient than commercial powder in the degradation of methylene blue. However, all lab-prepared powders were less efficient in killing E. coli. In the future, further modification on TiO2 will be carried out to produce powders which are more efficient than commercial ones.
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Qu, Meng-Chao, and 曲盟超. "Hydrogen Production by Composite Photocatalyst & Mechanism Analysis." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/71179539656795012913.
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碩士<br>國立臺灣大學<br>環境工程學研究所<br>103<br>We utilized crystalline flake graphite as one of the raw material to synthesize the graphene based semiconductor of photo-catalysts which are extensively concerned. In this research, the modified Hummers method was used to synthesize graphene, whereafter, CdS and WO3 powders were added into the material to compose the compound photo-catalysts for hydrogen production.
We further used instrument analysis such as FTIR, XRD, SEM/EDS and UV-Vis to confirm the crystal structure and the potential capability of photo-catalysis. The analysis includes, the optimal dosage and mixed ratio between different substances of compound semiconductor, the effect of doping Gr or N-Gr onto, the impact of WO3 in ternary hybrid and the different effects between three types of sacrificial reagents.
The results showed that all the materials including Graphite oxide、N-graphene、Graphene were successfully synthesized and the ideal crystal structure can promote the photo-catalysis effectively. In the contrary, N-graphene/CdS had negative effect comparing with expectation, but not the Gr/CdS. The Gr/CdS can perform the best efficiency and achieve the hydrogen productivity of 611μmol·h-1 after 5 hours reaction under the condition of using Na2S/Na2SO3 as sacrificial reagent with dosage of 0.4 grams.
This research testified the promising application of graphene based compound photo-catalysts that may be served as role materials in water splitting. However, further more details can be discussed in future researches to purify the compositions.
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陳勇智. "Drying agro-products by a photocatalyst solar dryer." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/49667891566700904308.
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碩士<br>國立屏東科技大學<br>食品科學系<br>92<br>Closed-type solar dryer has been developed to improve the performance of the traditional solar dryer. High transmittance glasses are used for complementing the heat from solar radiation, and dew-point technology is employed for dehumidify moisture to enhance drying efficiency. In addition, a heat reclaimable system plus TiO2 photocatalyst are designed to reduce contamination of products and improve the energy saving of the designed solar dryer. The results showed that solar drying with heat reclaimable system at 40~42℃ without switching on heater that would save about 67% electricity. The total count number of the drying cabinet is down from 21 CFU/g to 3 CFU/g, even lower to zero, that satisfy the specification of CNS working environment (below 15 CFU/g).The experiment results of the total count number showed that, for pineapple, there is196 CFU/g from hot air drying and 10 CFU/g from photocatalyst solar dryer, and it has higher vitamin C in that; for balsam pear, there is 430 CFU/g from hot air drying and 20 CFU/g from photocatalyst solar drying; for lotus, there is 186 CFU/g from hot air drying solar drying and 10 CFU/g from photocatalyst solar drying. Results of “L” “a” “b” values and sensory evaluation also indicated that the products from the designed solar dryer have the highest acceptance in every respect.
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Yang, Jing-Yi, and 楊靜怡. "Photocatalytic activity of carbon nanotube supported TiO2 photocatalyst." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/78552954350234675924.
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碩士<br>東海大學<br>環境科學與工程學系<br>96<br>Abstract
The main objective of this work is to coat multi-walled carbon nanotube surface with TiO2 and to investigate its photocatalytic activity. Commercial multi-walled carbon nanotubes were modified with nitric acid under microwave heating. The TiO2/MWCNT photocatalysts were prepared by sol-gel method under ultrasonic condition; they were characterized with BET, XRD, SEM, TEM, UV-Vis, XAS and photodegradation of methylene blue in water under ultraviolet illumination. The results show that the BET surface area of the catalysts is 72.4—167.6 m2/g . From XRD results, TiO2 is the photocatalyst composites calcined at 450 ◦C are in anatase form structure. SEM and TEM results indicate that TiO2 has been successfully deposited on the surface of multi-walled CNT. The UV-Vis and XAS results indicate the existence of interaction between TiO2 and MWCNT. The photocatalytic activities of the composite catalysts were evaluated by photodegradation of methylene blue under ultraviolet illumination. TiO2/MWCNT has better photocatalytic activity than both TiO2 and MWCNT. TiO2 coated on the surface of MWCNT could improve the efficiency of the photocatalytic reaction.
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Lin, Yu-Cheng, and 林于程. "Z-scheme overall water splitting over K4Nb6O17 photocatalyst." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/77657577587157549572.
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碩士<br>國立東華大學<br>材料科學與工程學系<br>101<br>In this study, we combine H2 evolution photocatalyst with O2 evolution photocatalyst, and use an aqueous NaI solution as I-/IO3- shuttle redox mediator in Z-scheme photocatalysis system for water splitting. We use solid state reaction to prepare H2 evolution photocatalyst, K4Nb6O17, and loading Rh as cocatalyst to improve hydrogen production. When the amount of loading Rh up to 1.5wt%, we get H2 evolution rate about 24mmol h-1 g-1 was higher than K4Nb6O17(337μmoleg-1h-1) as prepared. Then, we use exfoliation method to prepare our nanosheets photocatalyst, NS-K4Nb6O17, and loading Rh as cocatalyst, and exhibited a highest H2 evolution rate about 71 mmoleg-1h-1 when 1.5wt%Rh was loading.
O2 evolution photocatalyst use WO3 loading 0.5wt%Pt as cocatalyst. The rate of H2 evolution and O2 evolution under UV irradiation significantly changed with the concentration of NaI, and the pH value of the reactant solution. The H2 and O2 production rate of K4Nb6O17/WO3-0.5wt%Pt Z-scheme photocatalysis system was 263μmol h-1 g-1 and 126μmol h-1 g-1, respectively. The optimal NaI concentration of the reactant solution 4mM at pH = 11. The H2 evolution and O2 evolution rate of K4Nb6O17/WO3-0.5wt%Pt Z-scheme photocatalysis system were enhanced by loading Rh nanoparticles as cocatalyst(H2:533μmoleg-1h-1，O2:259μmoleg-1h-1). The Z-scheme photocatalysis system with NS-K4Nb6O17 -1.5 wt%Rh/WO3-0.5wt%Pt photocatalysts exhibited a highest photoactivity with a H2 evolution rate of 1329μmol h-1 g-1 and a O2 evolution rate of 341μmol h-1 g-1.
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Liang, Yung-Chen, and 梁詠蓁. "Applications and property of TiO2/Graphene Photocatalyst composites." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/63391183376234260612.
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碩士<br>國立勤益科技大學<br>化工與材料工程系<br>102<br>The photocatalyst materials are usually TiO2 due to its high photocatalytic performance. This article explores the TiO2 photocatalyst modified with four different graphene modified by hydrothermal/ calcining and hydrothermal method, and various mass ratio of the graphene. (Photocatalyst composites were label as TxYC, x: weight percent, Y: graphene species, C: Calcining). Photocatalyst composites were characterized by field-emission scanning electron microscope (FESEM), X-ray diffraction(XRD), Raman spectroscopy, UV-vis diffuse reflectance spectra(UV-vis DRS), Fourier Transform infrared spectroscopy (FTIR) and photoactivity tests. The absorption spectra of the samples are shown that the narrowing of the band gap of TiO2 occurred with graphene introduction. The band gap of TiO2 is 3.08 eV, whereas the band gap of the photocatalyst composite has been slightly reduced to 2.50 eV. XRD and Raman analysis were suggested that addition of graphene cannot change crystalline structure of TiO2(Degussa, P25). FTIR spectra show that the chemical bonding between the graphene and TiO2. In photocatalytic tests, the visible light photocatalytic activity of TxGOA and TxGH1 composite are enhanced greatly on decomposition of methylene blue (MB).The photocatalytic activities of T4GOA samples are superior to that of TiO2, the methylene blue decomposition efficiency reached 100% only 30 min under UV light.
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Lin, Kuan-Yu, and 林冠宇. "Hydrophobic Nanocomposite Photocatalyst for Photocatalytic Carbon Dioxide Hydrogenation." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/892fk7.
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碩士<br>國立臺灣大學<br>化學工程學研究所<br>105<br>Facing the serious global warming and energy crisis problem, photocatalytic reduction of carbon dioxide is one of the most promising solutions to solve both problems simultaneously. Previous studies show that the hydrogenation of carbon dioxide photoreduction process can make the reaction more thermodynamically favorable, therefore promoting the hydrocarbon yield.
In this research we prepared a set of photocatalysts with different hydrophobic properties, on the basis that the inferior ability of carbon dioxide to compete the active sites with water vapor during the carbon dioxide photoreduction process. Montmorillonite with excellent cation exchange ability were combined with titanium dioxide sol gel for the preparation of titanium pillared montmorillonite. With simple cation exchange process, the catalysts were obtained with different hydrophobicity by the control of surfactant addition. To clarify the structural, textural and thermal properties, series of characterizations, including UV-vis, XRD, TGA, TG-DTA, FE-SEM, EDS, FE-TEM, ICP-MS were performed.
Using 8W UVB pen ray lamp as the light source, the photocatalytic carbon dioxide reduction activity of the catalysts were studied in a single batch reactor. After 4 hours irradiation under a mixture of carbon dioxide, water vapor, and hydrogen system at 45°C, 50PtTiMt showed the best photoactivity, generating CO:18.59μmol/gcat and CH4:22.74μmol/gcat, quantum efficiency 0.04221% and the highest CH4 selectivity. In comparison with commercial titanium dioxide P25 catalyst, a two-fold enhancement was achieved. Based on the experiment and characterization information, titanium pillared montmorillonite showed significant difference in morphology, adsorption properties compared with original clay, and smaller crystallite size compared with titanium dioxide without montmorillonite. The hydrophobicity of the catalyst increase along with the increase of CTA+ addition. However, we postulate that when the CTA+ addition amount is very high, part of the CTA+ may adsorb on the active sites and affect the photoactivity. In this study, the optimal CTA+ addition amount at 50% cationic exchange ability. Finally, the roles of titanium dioxide, surfactant, and montmorillonite are also well discussed.