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Letteratura scientifica selezionata sul tema "MESOPOROUS ZNO"

Autore: Grafiati

Pubblicato: 11 settembre 2023

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Articoli di riviste sul tema "MESOPOROUS ZNO"

Xu, Hang, Tianlong Yu e Yi Liu. "Characteristics and Performance of Nanozinc Oxide/Mesoporous Silica Gel Photocatalytic Composite Prepared by a Sol-Gel Method". Journal of Nanomaterials 2015 (2015): 1–5. http://dx.doi.org/10.1155/2015/154865.

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Nano-ZnO loaded mesoporous SiO2was prepared by sol-gel technology as a photocatalytic composite. XRD, SEM, TEM, EDX, and N2sorption isotherms were used to characterize the nano-ZnO/mesoporous SiO2. Acid Red 18 was used as simulated pollutant to determine the photocatalytic performance of nano-ZnO/mesoporous SiO2under ultraviolet light and solar light. The results showed that 6.4 nm ZnO was obtained and immobilized on mesoporous SiO2. Compared to the mesoporous SiO2, the surface area and average pore width of nano-ZnO/mesoporous SiO2were reduced by 12 m2/g and 0.7 nm, respectively. 50% ZnO content in a composite calcinated at 200∘C exhibited the best photocatalytic activity. The removal of Acid Red 18 under solar irradiation was 10% higher than ultraviolet light.

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Pourdayhimi, Parisa, Pei Wen Koh, Hadi Nur e Siew Ling Lee. "Highly Crystalline Zinc Oxide/Mesoporous Hollow Silica Composites Synthesized at Low Temperature for the Photocatalytic Degradation of Sodium Dodecylbenzenesulfonate". Australian Journal of Chemistry 72, n. 4 (2019): 252. http://dx.doi.org/10.1071/ch18175.

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Highly crystalline ZnO/mesoporous hollow silica sphere (MHSS) composites have been successfully synthesized through an impregnation method at 323K without applying calcination. Three composites of different Zn/Si molar ratios of 1:2, 1:1, and 2:1 were prepared. X-Ray diffraction patterns confirmed the presence of highly crystalline ZnO in the materials. A layer of ZnO was formed on the MHSS as evidenced by field emission scanning electron microscopy analysis. Transmission electron microscopy analysis verified the mesoporous structure in ZnO/MHSS composites. N2 adsorption–desorption analysis indicated a type IV isotherm for 1ZnO/2MHSS and 1ZnO/1MHSS samples, confirming the presence of mesopores in the ZnO layer. It has been demonstrated that all the ZnO/MHSS composites exhibit a high photocatalytic activity towards sodium dodecylbenzenesulfonate degradation compared with bare ZnO under UV irradiation. A kinetic study showed that the photodegradation followed a second order model. Among the prepared composites, 1ZnO/1MHSS recorded the highest reaction rate of 6.03×10−3mM−1min−1 which is attributed to a high crystallinity and the monodispersity of a high amount of ZnO on MHSS.

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Hong, Min-Hee, Chang-Sun Park, Sangwoo Shin, Hyung Hee Cho, Won-Seon Seo, Young Soo Lim, Jung-Kun Lee e Hyung-Ho Park. "Effect of Surfactant Concentration Variation on the Thermoelectric Properties of Mesoporous ZnO". Journal of Nanomaterials 2013 (2013): 1–6. http://dx.doi.org/10.1155/2013/172504.

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The electrical and thermal conductivities and the Seebeck coefficient of mesoporous ZnO thin films were investigated to determine the change of their thermoelectric properties by controlling surfactant concentration in the mesoporous ZnO films, because the thermoelectric properties of mesoporous ZnO films can be influenced by the porosity of the mesoporous structures, which is primarily determined by surfactant concentration in the films. Mesoporous ZnO thin films were successfully synthesized by using sol-gel and evaporation-induced self-assembly processes. Zinc acetate dihydrate and Brij-76 were used as the starting material and pore structure-forming template, respectively. The porosity of mesoporous ZnO thin films increased from 29% to 40% with increasing surfactant molar ratio. Porosity can be easily altered by controlling the molar ratio of surfactant/precursor. The electrical and thermal conductivity and Seebeck coefficients showed a close correlation with the porosity of the films, indicating that the thermoelectric properties of thin films can be changed by altering their porosity. Mesoporous ZnO thin films with the highest porosity had the best thermoelectric properties (the lowest thermal conductivity and the highest Seebeck coefficient) of the films examined.

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Zhou, Zhiping, Kai Lu, Xiao Wei, Tongfan Hao, Yeqing Xu, Xiaodong Lv e Yufeng Zhang. "A mesoporous fluorescent sensor based on ZnO nanorods for the fluorescent detection and selective recognition of tetracycline". RSC Advances 6, n. 75 (2016): 71061–69. http://dx.doi.org/10.1039/c6ra14890e.

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Canto-Aguilar, Esdras J., Carlos A. González-Flores, Diecenia Peralta-Domínguez, José M. Andres-Castán, Renaud Demadrille, Manuel Rodríguez-Pérez e Gerko Oskam. "Electrodeposition of Simonkolleite as a Low-Temperature Route to Crystalline ZnO Films for Dye-Sensitized Solar Cells". Journal of The Electrochemical Society 169, n. 4 (1 aprile 2022): 042504. http://dx.doi.org/10.1149/1945-7111/ac62c8.

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A pulsed electrodeposition procedure has been developed to prepare macroporous films of the semiconducting mineral simonkolleite, Zn5(OH)8Cl2·H2O, on glass/FTO substrates. The morphology is characterized by the presence of smooth, micron-sized hexagonal platelets, and relatively thick films of 6 μm can be prepared in about 15 min. Simonkolleite can be transformed into crystalline, mesoporous ZnO using a relatively low temperature thermal treatment (250 °C). While the macrostructure of hexagonal platelets is maintained, they become mesoporous due to the removal of water and Cl−-containing reaction products. Dye-sensitized solar cells were fabricated with both simonkolleite and ZnO films, using the recently reported fully organic benzothiadiazole-based photosensitizer MG-207, and an electrolyte solution based on either the I−/I3 − or the Co(bpy)3 2+/3+ redox couple. An efficiency of 1.74% has been obtained for ZnO/MG-207/Co(bpy)3 2+/3+ solar cells, illustrating the promise of crystalline, mesoporous ZnO obtained via a low-temperature simonkolleite route for portable and lightweight devices based on flexible substrates.

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Hong, Min-Hee, Chang-Sun Park, Won-Seon Seo, Young Soo Lim, Jung-Kun Lee e Hyung-Ho Park. "Thermoelectric Properties of Al-Doped Mesoporous ZnO Thin Films". Journal of Nanomaterials 2013 (2013): 1–6. http://dx.doi.org/10.1155/2013/131537.

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Al-doped mesoporous ZnO thin films were synthesized by a sol-gel process and an evaporation-induced self-assembly process. In this work, the effects of Al doping concentration on the electrical conductivity and characterization of mesoporous ZnO thin films were investigated. By changing the Al doping concentration, ZnO grain growth is inhibited, and the mesoporous structure of ZnO is maintained during a relatively high temperature annealing process. The porosity of Al-doped mesoporous ZnO thin films increased slightly with increasing Al doping concentration. Finally, as electrical conductivity was increased as electrons were freed and pore structure was maintained by inhibiting grain growth, the thermoelectric property was enhanced with increasing Al concentration.

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Hong, Min-Hee, Wooje Han, Kyu-Yeon Lee e Hyung-Ho Park. "The thermoelectric properties of Au nanoparticle-incorporated Al-doped mesoporous ZnO thin films". Royal Society Open Science 6, n. 5 (maggio 2019): 181799. http://dx.doi.org/10.1098/rsos.181799.

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Mesoporous Al-doped ZnO thin films incorporated with gold nanoparticles (Au NPs) were synthesized using a sol–gel and evaporation-induced self-assembly process. In this study, the complementary effects of Au NP incorporation and Al doping on the thermoelectric properties of mesoporous ZnO thin films were analysed. The incorporated Au NPs induced an increase in electrical conductivity but a detriment in the pore arrangement of the mesoporous ZnO thin film, which was accompanied by a decrease in porosity. However, the addition of the Al dopant minimized the pore structural collapse because of the inhibition of the grain growth in the ZnO skeletal structure, resulting in the enhancement of the pore arrangement and porosity. When the Au NPs and Al dopant were added at the same time, the degradation in the pore structure was minimized and the electrical conductivity was effectively increased, but the absolute value of the Seebeck coefficient was decreased. However, as a result, the thermoelectric power factor was increased by 2.4 times compared to that of the pristine mesoporous ZnO thin film. It was found that co-introducing the Au NPs and Al doping to the mesoporous ZnO structure was effective in preserving the pore structure and increasing the electric conductivity, thereby enhancing the thermoelectric property of the mesoporous ZnO thin film.

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Pourdayhimi, Parisa, Pei Wen Koh, Mohamed Mohd Salleh, Hadi Nur e Siew Ling Lee. "Zinc Oxide Nanoparticles-Immobilized Mesoporous Hollow Silica Spheres for Photodegradation of Sodium Dodecylbenzenesulfonate". Australian Journal of Chemistry 69, n. 7 (2016): 790. http://dx.doi.org/10.1071/ch15495.

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ZnO-Immobilized mesoporous hollow silica spheres (ZnO/xMHSS; x = 15, 30, 50 molar ratio of Zn/Si) were synthesized and examined as photocatalysts toward the degradation of sodium dodecylbenzenesulfonate (SDBS). The hollow structures of MHSS and ZnO-immobilized MHSS composite were evidenced by transmission electron microscopy analysis. X-ray diffraction results confirmed the presence of ZnO and a mesoporous structure in the synthesized materials. N2 adsorption–desorption analysis also depicted the formation of a mesoporous structure and the increased surface area for the ZnO/xMHSS materials. Fourier transform infrared spectroscopy analysis revealed the formation of Si–O–Zn bonds due to interaction between ZnO and MHSS. The photocatalytic testing results indicated that all the ZnO/xMHSS materials showed improved efficiencies of 10–21 % toward the photodegradation of SDBS when compared with bare ZnO. Among the prepared materials, ZnO/15MHSS was the best photocatalyst, which photodegraded 68 % SDBS after 1 h reaction. The kinetic study demonstrated that the photocatalytic reaction followed the second-order model.

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SINGH, SARIKA, K. C. BARICK e D. BAHADUR. "NOVEL AND EFFICIENT THREE DIMENSIONAL MESOPOROUS ZnO NANOASSEMBLIES FOR ENVIRNOMENTAL REMEDIATION". International Journal of Nanoscience 10, n. 04n05 (agosto 2011): 1001–5. http://dx.doi.org/10.1142/s0219581x11008654.

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This work demonstrates the fabrication of a novel three-dimensional (3D) mesoporous spherical ZnO nanoassembly by soft-chemical approach. XRD analysis revealed the formation of single phase hexagonal wurtzite nanostructure. It has been observed that each nanoassembly (100–600 nm) is comprised of numerous nanocrystals of size about 20 nm. These assemblies are fairly stable, well-defined, discrete and porous. The predominance of mesopores is evident from TEM and porosity measurements. Methylene blue (MB) was used as model dye to investigate the photocatalytic activity of ZnO nanoassemblies. These nanoassemblies have good photocatalytic performance due to its unique porous 3D nanostructure having defects. Furthermore, the ZnO nanoassemblies were also explored for the purification toxic metal ions such as Co2+ , Ni2+ , Cu2+ , Cd2+ , Pb2+ , Hg2+ and As3+ from waste-water.

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Zhang, Hui, Chen Chen, Xiao Long Xu, Rong Wu, Fan Li e Mei Zhang. "Syntheses of Mesoporous ZnO and SnO₂ Microspheres by Spray Reaction Process". Key Engineering Materials 519 (luglio 2012): 74–78. http://dx.doi.org/10.4028/www.scientific.net/kem.519.74.

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For the first time, mesoporous ZnO and SnO2 spherical particles were synthesized by spray reaction (SR) process. The synthesized materials were characterized by thermo-gravimetry/differential thermal analysis (TG/DTA), scanning electron microscopy (SEM), and X-ray diffraction (XRD). Results reveal that few ZnO microspheres were formed after calcined at 700 °C while large quantity of non-spherical ZnO particles was produced. And the predominant hexagonal ZnO (h-ZnO) is attained when heated at 700 °C. Mesoporous SnO2 microspheres prepared at 800 °C possess an average size ~2.22 μm and a major tetragonal phase (t- SnO2) with crystallite size 7.8 nm.

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Più fonti

Tesi sul tema "MESOPOROUS ZNO"

Fall, Safall. "Fabrication et analyse de nanomatériaux à bases d'oxydes par des techniques de diffusion de rayonnement". Phd thesis, Université du Maine, 2011. http://tel.archives-ouvertes.fr/tel-00607031.

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Ce travail de thèse porte sur l'étude d'oxydes (ZnO et SiO2) fabriqués par voie sol-gel. Dans un premier temps, nous avons étudié la cinétique de croissance des nanoparticules de ZnO en milieu aqueux. L'étude in-situ de la croissance d'oxyde de zinc par la technique de croissance en milieu aqueux (ACG) a été réalisée grâce à la radiation synchrotron de l'ESRF sur la ligne ID10B. Nous avons réalisé la diffraction de rayons X en incidence rasante sur un substrat plongé dans une solution constituée de nitrate de zinc hexahydraté [Zn(NO3)2,6H2O], d'hexamethylenetetramine (HMT) (C6H12N4) et de l'eau dé-ionisée comme solvant. Nous avons réussi à mettre en évidence l'existence de nanoparticules de ZnO dans la solution et suivre la cinétique de formation. La deuxième partie de ce travail est consacrée à l'étude des films minces de silice mésoporeux structurés par un tensioactif connu sous l'acronyme Brij58. Nous avons commencépar établir le diagramme de phase du Brij58 par la diffusion centrale des rayons X (SAXS), complété par l'établissement d'un diagramme d'état solide-liquide par la rhéologie. Grâce à ce diagramme de phase nous avons pu fabriquer des films minces de silice. L'étude de la structuration des films a été réalisée par la diffusion des rayons X en incidence rasante (GISAXS) et la réflectivité des rayons X. Nous avons finalisé ce travail par l'utilisation des films mésoporeux comme matrice hôte à deux fluides : l'eau et le CO2, et par l'insertion de nanocristaux de ZnO dans les pores de la matrice mésoporeuse.

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Nygren, Kristian. "Solar cells based on synthesized nanocrystalline ZnO thin films sensitized by chlorophyll a and photopigments isolated from spinach". Thesis, Linköping University, Department of Physics, Chemistry and Biology, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-55032.

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The principles of dye-sensitized solar cells were studied and are outlined in this thesis. An overview of the basic steps needed to create a DSC isfollowed by detailed experimental information on how to assemble the solar cells that were fabricated in this project. They were based on synthesizednanocrystalline ZnO thin films sensitized by chlorophyll a as well as isolated photopigments from spinach leaves. The nanocrystals werestudied using XRD, and it was confirmed that three different methods of synthesis resulted in ZnO crystals of a few nanometers. The solar cellswere assembled with Au electrodes in a sandwich configuration and their photovoltaic properties were measured. Overall light-to-electricity conversionwas low with the highest efficiency being 0.21 %. An astonishingly low efficiency of 0.0003 % was noted for a thin film which was not thermallytreated, and it is suggested that heat-treatment is of great importance. It was also found that photopigments from spinach can be extractedeasily and used as molecular sensitizer without any demanding purification steps.

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Großmann, Dennis [Verfasser], Wolfgang [Gutachter] Grünert e Martin [Gutachter] Muhler. "Methanol synthesis over Cu/ZnO aggregates encapsulated in carbon nanotubes and mesoporous silica / Dennis Großmann ; Gutachter: Wolfgang Grünert, Martin Muhler ; Fakultät für Chemie und Biochemie". Bochum : Ruhr-Universität Bochum, 2013. http://d-nb.info/1214440746/34.

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Oliveira, Cristine Santos de 1990. "Sistemas nanoestruturados de ZnO contendo Eu3+ em sílica mesoporosa". [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/250543.

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Orientador: Ítalo Odone Mazali
Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química
Made available in DSpace on 2018-08-22T20:07:38Z (GMT). No. of bitstreams: 1 Oliveira_CristineSantosde_M.pdf: 3527061 bytes, checksum: 7dfe90cc79337811bc7955e8a1531586 (MD5) Previous issue date: 2013
Resumo: O trabalho consistiu na síntese de sistemas nanoestruturados de ZnO contendo Eu em sílica mesoporosa, o vidro poroso Vycor (PVG), utilizando o método de ciclos de impregnação-decomposição (CIDs). Sistemas de nanopartículas puras de ZnO, na forma PVG/10ZnO mostraram que o ZnO apresentou-se predominantemente na forma de sítios de ZnO monodispersos com absorção em 245-250 nm e na forma de nanopartículas, com tamanho médio em torno de 4,5 nm, para as quais inicialmente não se observou uma absorção característica. Através de espectroscopia de luminescência observou-se transferência de energia do ZnO monodisperso para a matriz, porém nenhuma emissão no visível característica de defeitos. Para o sistema PVG/10Eu observou-se transições f-f características nos espectros de emissão e excitação, e a transferência de carga O¿¿Eu. Os sistemas seguintes sintetizados na forma PVG/ZnO@ZnO/M@ZnO, com M = Eu, Al, Sr, Pr e Yb visaram o estudo do sistema principal PVG/ZnO@ZnO/Eu@ZnO, o qual apresentou emissões do Eu relativamente mais intensas do que no sistema PVG/10Eu além de apresentar o favorecimento do crescimento do ZnO sob a forma de nanopartículas, crescendo sobre os aglomerados de dopante. Nessas condições, surge a banda proibida do ZnO em torno de 360 nm, cuja borda é deslocada para menores energias com o número de CIDs, em acordo com uma equação da literatura, indicando um regime de confinamento quântico. Esta banda é observada na luminescência e também transfere energia para a matriz, ainda não sendo observadas emissões de defeitos do ZnO. Estudos com Sr e Al não confirmaram a formação de defeito do tipo Zni decorrente da inserção do íon Eu na rede do óxido. Os espectros de excitação para os sistemas de ZnO contendo Eu não foram conclusivos quanto à transferência de energia devido à presença de bandas do Eu, e num sistema similar substituindo-se por Yb não foi observada esta transferência. Medidas de tempo de vida mostraram um aumento da estabilidade do Eu no sistema com a presença prévia do ZnO, e também sob seu recobrimento. Através das emissões excitônicas do ZnO observou-se o efeito de confinamento quântico também na luminescência, o qual se deu de forma similar ao observado para a análise por absorção no UV-Vis
Abstract: The work consisted in the synthesis of nanostructured systems of ZnO containing Eu loaded in a mesoporous silica, the porous Vycor glass (PVG), using the impregnation-decomposition cycles method (IDCs). Pure ZnO nanoparticles systems synthesized in the form PVG/10ZnO have shown that ZnO presents itself predominantly as monodisperse ZnO sites with absorption at 245-250 nm, and nanoparticles, with mean size around 4,5 nm, for which initially no characteristic absorption had been observed. Through luminescence spectroscopy an energy transfer from monodisperse ZnO to the matrix was observed, but no defect-related emissions. For the PVG/10Eu system Eu characteristic f-f transitions were observed in both emission and excitation spectra, as well as the O¿¿Eu charge transfer. The following systems synthesized in a PVG/ZnO@ZnO/M@ZnO pattern, with M = Eu, Al, Sr, Pr e Yb sought the study of the main system PVG/ZnO@ZnO/Eu@ZnO, which presented Eu emissions relatively more intense than the PVG/10Eu system, also showing favoring growth of ZnO under the form of nanoparticles, which now grow over dopant clusters. Under such condition the ZnO band gap is now observed in UV-Vis absorption analysis, with peaks around 360 nm, whose edge is displaced towards lower energies with increasing number of IDCs, also in agreement with a theoretical equation from the literature, pointing to a condition of quantum confinement. This band is observed in luminescence, and also transfers energy to the matrix, and yet no defect-related emissions are observed for ZnO. Studies with Sr and Al did not confirm the formation of a Zni defect due to the insertion of Eu ions into the oxidefs structure. Excitation spectra for Eu-containing ZnO systems were not conclusive as to the existence of an energy transfer due to the presence of Eu bands in the same range, and in the similar system exchanging Eu3+ for Yb3+ such transfer was not observed. Lifetime measurements have shown an increase in Eu stability within the system with ZnO presence previous to its insertion, or after its coating layer(s). Quantum confinement effect was also observed for the ZnO excitonic emissions in luminescence, showing a similar behavior to that obtained thru UV-Vis absorption analysis
Mestrado
Quimica Inorganica
Mestre em Química

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Sivaram, Varun. "Simulation, synthesis, sunlight : enhancing electronic transport in solid-state dye-sensitized solar cells". Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:0824a954-e9a9-4f14-a6b4-675652d01d4e.

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The solid-state dye sensitized solar cell (SDSC) is an emerging photovoltaic technology which promises inexpensive materials, roll-to-roll processing, and a stable architecture. In this thesis, I seek to enhance electronic transport in order to enable thicker devices and yield higher power conversion efficiencies. I adopt a multipronged approach to advance three aims, employing analytical, computational, and experimental methodologies. First, I generalize existing models of the dye sensitized solar cell (DSSC) to allow simple parameter fitting of real devices and to account for previously ignored electronic processes. In Chapter 3 and Chapter 4 I present a nondimensional model capable of fitting real devices and simulating transient behavior without extensive material knowledge. Subsequently in Chapter 5, I introduce a novel three-dimensional model which incorporates electronic drift. Second, in Chapter 4 I critically assess a widespread method of measuring the charge collection efficiency, the summary metric that describes the efficacy of charge transport in the SDSC. I discover that the conventional method is inaccurate for values of the collection efficiency below 90% because of large experimental error and an intrinsic inaccuracy in applying a transient method to measure a steady-state parameter. Third, I aim to increase the rate of charge transport by employing new materials and nanostructures in the place of conventional nanocrystalline TiO2. In Chapter 5, I present evidence of faster transport and enhanced efficiency in flexible SnO2 nanowire SDSCs, ZnO nanowire SDSCs, and the first viable SnO2/P3HT SDSC, where photoanode and hole transporter have been replaced with higher mobility materials. Finally, in Chapter 6, I investigate use of TiO2 mesoporous single crystals (MSCs) with high surface area and extended crystallinity. After demonstrating the viability of MSCs in SDSCs, I examine enhanced transport caused by the background doping effect of thermal treatment. Together, the progress achieved toward diverse and ambitious goals advances the field and delineates routes to future progress for SDSC development.

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KUSHWAHA, PREETI. "SYNTHESIS OF ZnO AND ITS PHOTOCATALYTIC ACTIVITY". Thesis, 2016. http://dspace.dtu.ac.in:8080/jspui/handle/repository/14897.

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In the present work, mesoporous ZnO are successfully prepared with the help of hydrothermal method and sol gel method. Zinc nitrate hexahydrate, ctab, urea are used as precursor materials. The ZnO powder obtained is calcined at 800 0C and analyzed different properties and behavior of nanoparticles. The method which is used ,has been implicated with some modification with the aim to reduce the size of nanoparticles followed by the paper, and changes are studied with the help of different experimental characterization as XRD conferred ZnO, SEM and TEM revealed different morphology, shape and structure of particles. BET gives pores size and diameter, advantage of lesser size of particles with pores of having large surface area due to which it will take less time to degrade dye which is required and present research need for efficient applications and then determining the photocatalytic degradation of rhodamine-b dye on mesoporous ZnO nanoparticles. Photocatalysis is a well defined approach in which UV light energy is focussed to excite the semiconductor material producing electron/hole pair which eventually involves in the detoxification of pollutants (in water or air) and water splitting. Existing photocatalysts suffer from poor activity or no activity in visible light irradiation which restricts them from solar light utilization. Photocatalytic oxidation processes with ultra violet (UV) radiation and semiconductor photocatalyst like zinc oxide (ZnO) have gained an interest as an effective wastewater purification method because of its efficacy in decomposing and mineralising the hazardous organic pollutants and also utilizing the solar UV and visible spectrum. Rhodamine B is a significant dye. Color is one of the vital characteristics of these effluent streams and seems to be the most undesired, as it affects the nature of water by inhibiting sunlight penetration hence reducing photosynthetic action. Thus, to remove color from industrial effluents is a major concern in wastewater treatment, and treatment is needed before discharging to receiving water. To remove dye pollutants there are various conventional methods such as adsorption on activated carbon, ultra filtration, reverse osmosis, coagulation by chemical agent etc. The pollutants cannot be completely degraded by given methods, the incapability of conventional methods to effectively remove pollutants leads to discover new, efficient and cost effective methods. Photocatalytic process relies on the activation of semiconductor that gives generation of electrons /holes. These holes can react with water to produce hydroxyl radical which results inseries of redox reaction to destroy the pollutants. ZnO has been demonstrated to be an excellent catalyst.

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Chang, Wen-Hsuan, e 張文瑄. "ZnO and MgO nanoparticles confined in 3D mesoporous carbon as efficient nanocomposite anodes for lithium-ion batteries". Thesis, 2017. http://ndltd.ncl.edu.tw/handle/rm6cgw.

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碩士
國立中央大學
化學學系
105
Trainsition metal oxide as anode materials in lithium ion batteries have attracted tremendous attention in the past few years because of their characterstics.ZnO is regarded as one of the most promising anode material for lithium ion batteries (LIBs), due to its high theoretical capacity (978 mAh/g), natural abundance, and low cost. Although MgO is electrochemically inactive, its adsorption capacity towards liquid electrolyte functioning as a protective coating and enhancement in ionic conductivity encourages the use of a MgO-decorated composite as an anode for LIBs. The ZnO@CMK-8 and MgO@CMK-8 nanocomposites, composed of ultrafine ZnO and MgO nanoparticles encapsulated in three dimensional (3D) ordered mesoporous carbon CMK-8, has been successfully synthesized and served as promising anode materials in lithium-ion batteries (LIBs) with different concertration, separately. The prepared ZnO@CMK-8 and MgO@CMK-8 have been characterized by various techniques, such as XRD, nitrogen adsorption-desorption, high-resolution TEM, and SEM measurements. Our characterization results demonstrates that both ZnO and MgO nanoparticles can be incorporated into the mesopores of CMK-8 with high dispersion and small particle sizes. As anode materials in lithium ion batteries the composites ZnO@CMK-8-0.5M displays higher initial discharge capacity(2214 mAh/g) than bulk ZnO. MgO@CMK-8-10wt% also demonstrates the better results(744 mAh/g) than rude MgO.

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Li, Hsiang-Tien, e 李享典. "Synthesis and Identification of ZnS Quantum Dot Inside Layered and Mesoporous Materials and Their Application in Photocatalytic Reactions". Thesis, 2010. http://ndltd.ncl.edu.tw/handle/64935406401690061802.

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碩士
國立中興大學
化學系所
98
Greenhouse gases have caused global climate anomalies, and it will be more serious within the next few years. Therefore the reduction of carbon dioxide indeed becomes indispensable. The apporach of this study is to adsorb the carbon dioxide from the air to in a matrix with excellent CO2 adsorption capacity. Then carbon dioxide reduction is performed by using light to excite semiconductor photocatalyst to generate electron-hole pair. The matrices used in this study includes Layered Double Hydroxide (LDH) and SBA-15 mesoporous materials. LDH is a good gas matrix to adsorb carbon dioxide. SBA-15 with higher surface area and pore structure are also good for gas adsorption capacity. The use of zinc sulfide (ZnS) quantum dot as semiconductor photocatalyst is due to its high band gap as compared to other semiconductor photocatalyst. This band gap enables this quantum dot to perform the photocatalytic reduction of carbon dioxide.

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Capitoli di libri sul tema "MESOPOROUS ZNO"

Zhao, Chun Xia, Wen Chen, Qi Liu e Li Qiang Mai. "Spectroscopic Study of Rod-Like Mesoporous ZnO-SiO₂ Composites". In Key Engineering Materials, 2267–70. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-410-3.2267.

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Chen, Haining, Liqun Zhu, Weiping Li e Huicong Liu. "Electrodeposition of ZnO Nanocrystallines on ITO Mesoporous Films and Application to Photoelectrochemical Cells". In Supplemental Proceedings, 465–72. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2011. http://dx.doi.org/10.1002/9781118062111.ch52.

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Manujlov, Eugene, Yuriy Gnatyuk, Vera Vorobets, Gennadiy Kolbasov, Natalia Smirnova, Anna Eremenko, Asta Guobiené e Sigitas Tamulevičius. "Mesoporous TiO2 and TiO2/ZnO/Ag films: Sol-Gel Synthesis, Photoelectrochemical and Photocatalytic Properties". In Sol-Gel Methods for Materials Processing, 427–34. Dordrecht: Springer Netherlands, 2008. http://dx.doi.org/10.1007/978-1-4020-8514-7_38.

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Ahmed, Fadi Ibrahim. "Synthesis of Novel Virus-Like Mesoporous Silica-ZnO-Ag Nanoparticles and Quercetin Synergize with NIR Laser for Omicron Mutated Covid-19 Virus Infectious Diseases Treatment". In Research Advances in Microbiology and Biotechnology Vol. 2, 63–75. B P International (a part of SCIENCEDOMAIN International), 2023. http://dx.doi.org/10.9734/bpi/ramb/v2/3792a.

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Atti di convegni sul tema "MESOPOROUS ZNO"

Abdul-kareem, Asma Abdulgader, Noura AlSanari, Amal Daifallah, Radwa Mohamed, Jolly Bhadra, Deepalekshmi Ponnamma e Noora Al-Thani. "Piezoelectric Nanogenerators based on Pvdf-Hfp/Zno Mesoporous Silica Nanocomposites for Self-Powering Devices". In Qatar University Annual Research Forum & Exhibition. Qatar University Press, 2020. http://dx.doi.org/10.29117/quarfe.2020.0054.

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Abstract (sommario):

Due to the rising global concern over energy catastrophe and environmental issues, attention has been diverted towards future energy. In recent times, rechargeable power and renewable energy sources have been considered as an attractive substitute for resolving the future environmental problems. Among them, mechanical energy is one of the most abundant energy sources, and easily transformable to other useful energy forms, such as electrical energy. For such purposes, piezoelectric materials with ability to convert the mechanical energy generated by various activities into electrical energy. In this research work, we have investigated the morphology, structure and piezoelectric performances of neat polyvinylidene fluoride hexafluoropropylene (PVDF-HFP), PVDF-HFP/ZnO, PVDFHFP/ Mesoporous silica, PVDF-HFP 1% and PVDF-HFP 3% ZnO-Mesoporous silica nanofibers, fabricated by electrospinning. Both SEM and TEM images of ZnO nanoparticles shows formation of uniform flake of about 5nm diameter and Mesoporous silica shows uniform spherical morphology with average diameter of 5 μm. EDX plot justifies the presences of Zn, O and Si. An increase in the amount of crystalline β-phase of PVDF-HFP has been observed with the introduction of ZnO and mesoporous silica in the PVDF-HFP matrix are observed in FTIR spectra. All the XRD peaks observed in neat PVDF has the strongest intensity compared to rest of the other XRD peaks of polymer nanocomposite. The XRD spectra of all the nanocomposites have peaks at 17.8°, 18.6° correspond to α- crystalline phase, the peaks observed at 19°, 20.1° correspond to the γ- crystalline phase, and the peak at 20.6° corresponds to the β- crystalline phase. The flexible nanogenerator manipulated from the polymer nanocomposite with 1% ZnO-Mesoporous silica exhibits an output voltage as high as 2 V compared with the neat PVDF-HFP sample (~120 mV). These results indicate that the investigated nanocomposite is appropriate for fabricating various flexible and wearable self-powered electrical devices and systems.

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Pauporté, T. "Electrochemical growth of ZnO nanocolumn arrays and ZnO mesoporous films". In SPIE OPTO: Integrated Optoelectronic Devices, a cura di Ferechteh H. Teherani, Cole W. Litton e David J. Rogers. SPIE, 2009. http://dx.doi.org/10.1117/12.808515.

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Wu, Qishuang, Yue Shen, Guizhi Wu, Linyu Li, Meng Cao e Feng Gu. "Natural dye -sensitized mesoporous ZnO solar cell". In Seventh International Conference on Thin Film Physics and Applications, a cura di Junhao Chu e Zhanshan Wang. SPIE, 2010. http://dx.doi.org/10.1117/12.888318.

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Wu, Guizhi, Yue Shen, Wanxi Cheng, Feng Gu, Jiancheng Zhang e Linjun Wang. "Photoelectric properties of a-Si/mesoporous ZnO tandem solar cells". In Seventh International Conference on Thin Film Physics and Applications, a cura di Junhao Chu e Zhanshan Wang. SPIE, 2010. http://dx.doi.org/10.1117/12.888204.

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Aykaç, Ahmet, e İzel Ok. "Investigations and Concerns about the Fate of Transgenic DNA and Protein in Livestock". In International Students Science Congress. Izmir International Guest Student Association, 2021. http://dx.doi.org/10.52460/issc.2021.046.

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Hydrogels are biocompatible and swollen materials that have been used as a wound dressing for years. Among them, chitosan-based hydrogels have become popular in the wound healing process owing to their low toxic, biocompatible, biodegradable, antibacterial properties. Chitosan (CS) has been used either as a pure form or incorporated with polymers or nanoparticles to increase antimicrobial activity and stability. In this context, zinc oxide nanoparticles (ZnO NPs) have been used to enhance antibacterial activity and mesoporous silica nanoparticles (MSN) have been employed to develop mechanical strength and control of drug release time. In this study, we report the synthesis and fully characterizations of ZnO NPs, MSN and the hydrogel by using dynamic light scattering (DLS), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR). We have also prepared and characterized chitosan-based hydrogels functionalized by MSNs and ZnO NPs.

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Li, Linyu, Yue Shen, Qishuang Wu, Meng Cao, Feng Gu e Jiancheng Zhang. "Influence of ion-doping on the photoelectric properties of mesoporous ZnO thin films". In Seventh International Conference on Thin Film Physics and Applications, a cura di Junhao Chu e Zhanshan Wang. SPIE, 2010. http://dx.doi.org/10.1117/12.888217.

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Sowri Babu, K., A. R. C. Reddy, Ch Sujatha, K. V. G. Reddy e N. K. Mishra. "Observation of excitation wavelength dependent photoluminescence from ZnO nanoparticles embedded in mesoporous silica". In SOLID STATE PHYSICS: PROCEEDINGS OF THE 57TH DAE SOLID STATE PHYSICS SYMPOSIUM 2012. AIP, 2013. http://dx.doi.org/10.1063/1.4790982.

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Sett, Avik, Anand Kumar Mukhopadhyay, Monojit Mondal, Santanab Majumder e Tarun Kanti Bhattacharyya. "Tuning Surface Defects of Mesoporous ZnO Nanorods for High Speed Humidity Sensing Application". In 2018 IEEE Sensors. IEEE, 2018. http://dx.doi.org/10.1109/icsens.2018.8589790.

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Yanglin Liu, Xuechen Duan e Yajuan Cheng. "Study on preparation of ZnO doped Mesoporous TiO2 Microspheres and its Photocatalytic properties". In 2011 International Conference on Remote Sensing, Environment and Transportation Engineering (RSETE). IEEE, 2011. http://dx.doi.org/10.1109/rsete.2011.5965811.

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Wu, Mingming, Yue Shen, Feng Gu, Yun Zhang, Yian Xie e Jiancheng Zhang. "Preparation and photoelectric properties of mesoporous ZnO/TiO 2 composite films for DSSC". In Photonics and Optoelectronics Meetings 2009, a cura di Michael Grätzel, Hiroshi Amano, Chin Hsin Chen, Changqing Chen e Peng Wang. SPIE, 2009. http://dx.doi.org/10.1117/12.843356.

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