Download or read book Structural and Morphological Modification of TiO2 Doped Metal Ions and Investigation of Photo induced Charge Transfer Processes written by Jesus Vargas Hernandez and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The thesis work is focused on the synthesis methods of titanium dioxide nanostructures and their physico-chemical studies in order to point out the correlations between the morphology, metal doping, structural features with the photocatalytic efficiency. The great interest on TiO2 nanomaterials deals with new sources of energy or in the environment preservation through the photocatalytic properties. However, the main limitations is due to the wide band gap (~3.2 eV) of the anatase polymorph. Thus, a major objective for improvement of the performance of TiO2 nanomaterials is to increase theirphotoactivity by shifting the onset of the electron-hole pairs creation from UV to the visible range. Moreover, it was found that using onedimensional (1-D) TiO2 (nanotubes) improved the charge collection by 1D nanostructures which consequently minimizes the recombination and prolongate the electron lifetimes. The first part of this work is focused on the synthesis of TiO2 nanopowders doped with metallic ions (Ag, Cu, Eu) prepared by Solgel. Even with different doping elements which apparently can adopt the same valence state (2+) such as (Cu2+, Ag2+,Eu2+), different behaviors were demonstrated for the effective incorporation of these ions in the host structure of TiO2. The discrepancy between ionic radii of the different used elements modulates the ratio of the substitutional doping. This is indeed achieved for Cu2+ but in less extent for Ag2+ while Europium ions form segregated phase as Eu2Ti2O7. The experiments on the degradation of methylene blue (MB)dyes have shown slight improvement with Ag-doped samples. The reason was tentatively attributed to the Ag clusters which were indeed demonstrated through their plasmon optical band. The second part of the work concerns thin films of TiO2 doped (Cu, Ag, and Eu) which were elaborated by spin coating and dip coating. The optimal parameters were obtained to achieve crystalline films but presenting mesoporous organisation which also depends on the doping process. Photocatalysis investigations were also realized and the efficiency of the films compared as function of the doping elements.The third part of the thesis is related to the morphological modification from nanoparticles to nanotubes by using the hydrothermal method with controlled pressure. An experimental design based on Taguchi Method was employed for the determination of the optimal parameters. TiO2 nanotubes increase the surface area in comparison with TiO2nanoparticles. TiO2 nanotubes were tested for the methylene blue degradation and show a higher photocatalytic efficiency than TiO2 nanopowders and TIO2 doped with Ag.
Download or read book Basic Concepts of Data and Error Analysis written by Panayiotis Nicos Kaloyerou and published by Springer. This book was released on 2018-10-24 with total page 269 pages. Available in PDF, EPUB and Kindle. Book excerpt: This introductory textbook explains the concepts and methods of data and error analysis needed for laboratory experiment write-ups, especially physics and engineering experiments. The book contains the material needed for beginning students, e.g., first year university students, college students (enrolled on a certificate or diploma course) and even A-level students. Nevertheless, it also covers the required material for higher year university laboratories, including the final year. Only essential concepts and methods needed for the day-to-day performance of experiments and their subsequent analysis and presentation are included and, at the same time, presented as simply as possible. Non-essential detail is avoided. Chapter five is a stand-alone introduction to probability and statistics aimed at providing a theoretical background to the data and error analysis chapters one to four. Computer methods are introduced in Chapter six. The author hopes this book will serve as a constant reference.
Download or read book Semiconductor Photocatalysis written by Wenbin Cao and published by BoD – Books on Demand. This book was released on 2016-08-24 with total page 678 pages. Available in PDF, EPUB and Kindle. Book excerpt: Photocatalysis is a hot topic because it is an environmentally friendly approach toward the conversion of light energy into chemical energy at mild reaction environments. Also, it is well applied in several major areas such as water splitting, bacterial inactivation, and pollutants elimination, which is a possible solution to energy shortage and environmental issues. The fundamental knowledge and the frontier research progress in typical photocatalytic materials, such as TiO2-based and non-TiO2-based photocatalysts, are included in this book. Methods to improve the photocatalytic efficiency and to provide a hint for the rational design of the new photocatalysts are covered.
Download or read book Photocatalysts written by Sher Bahadar Khan and published by BoD – Books on Demand. This book was released on 2019-03-06 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book enlightens the type, chemical structure, and application of photo-catalysts. It covers the recent developments in photo-catalysts and their applications, particularly in photo-catalytic degradation of different organic pollutants, hydrogen production, etc. It provides a concise but complete coverage and overview of photocatalysts and their recent advances for a broad audience: beginners, graduate students, and specialists in both academic and industrial sectors.
Download or read book Rare Earth Doped Anatase TiO2 Nanoparticles written by Vesna Đorđević and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Titanium dioxide is a wide band-gap semiconductor of high chemical stability, nontoxicity and large refractive index. Because of the high photocatalytic activity, anatase is a preferred TiO2 form in many applications such as for air and water splitting and purification. Doping of TiO2 with various ions can increase the photocatalytic activity by enhancing light absorption in visible region and can alter structure, surface area and morphology. Also, by doping TiO2 with optically active ions, visible light via up- or downconversion luminescence can be produced. It is a challenge to optimize the synthesis procedure to incorporate rare earth RE3+ ions into the TiO2 structure due to large mismatch in ionic radii between the Ti4+ and RE3+ and because of the charge imbalance. Visible (VIS) and ultraviolet (UV) luminescence of several RE3+ ions can be obtained when incorporated into anatase TiO2, also affecting microstructural characteristics of TiO2. It is of great importance to summarize publications on rare earth-doped anatase TiO2 nanoparticles to find correct TiO2-RE combination to sensitize trivalent rare earths luminescence, as well as to predict or tune structural and morphological properties. A better understanding on these topics may progress the desired design of this kind of material towards specific applications.
Download or read book Updates on Titanium Dioxide written by Bochra Bejaoui and published by BoD – Books on Demand. This book was released on 2023-08-30 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: Titanium dioxide (TiO2) has received a lot of attention due to its inexpensive cost, benign nature, and great photocatalytic potential. TiO2 has numerous applications, including in photocatalysts, Li-ion batteries, solar cells, and medical research. However, its performance is unsatisfactory due to a variety of issues, including a wide band gap (3.01 to 3.2 eV) and quick electron–hole pair recombination (1012 to 1011 s). Many efforts have been made to improve the qualities of TiO2, such as structural and dopant changes, which expand its applications. This book focuses on the properties of TiO2-modified nanoparticles, including their synthesis, alterations, and applications.
Download or read book Heterogeneous Photochemical Electron Transfer written by Michael Gratzel and published by . This book was released on 1989 with total page 159 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hierarchical Nanostructures for Energy Devices written by Seung H Ko and published by Royal Society of Chemistry. This book was released on 2014-10-29 with total page 323 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface area has a directly relationship with the efficiency of energy devices. Hierarchical nanostructuring has the potential to greatly increase surface area, and their electrical properties are favourable, not only to energy generation and storage, but also energy-consuming electronic circuits. This book provides systematic coverage of how nanostructured materials can be applied to energy devices, with an emphasis on the process of generation to storage and consumption. The fundamentals (including properties, characterisation and synthesis) are clearly presented across the first chapters of the book, providing readers new to the field with a clear overview of this expanding topic. The detailed discussion of applications will be an inspiration to those already well-versed in the field. The editors have more than a decade of experience in working on all aspects of energy generation and storage - in academia, national laboratories and industry. The book presents a balanced view from all sectors and is presented in a format accessible by postgraduate students and professional researchers alike.
Download or read book Surface Modifications and Growth of Titanium Dioxide for Photo Electrochemical Water Splitting written by John Alexander and published by Springer. This book was released on 2016-05-21 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt: This outstanding thesis provides a wide-ranging overview of the growth of titanium dioxide thin films and its use in photo-electrochemicals such as water splitting. The context for water splitting is introduced with the theory of semiconductor-liquid junctions, which are dealt with in detail. In particular plasmonic enhancement of TiO2 by the addition of gold nanoparticles is considered in depth, including a thorough and critical review of the literature, which discusses the possible mechanisms that may be at work. Plasmonic enhancement is demonstrated with gold nanoparticles on Nb-doped TiO2. Finally, the use of temperature and pressure to control the phase and morphology of thin films grown by pulsed laser deposition is presented.
Download or read book Nanoscale Materials in Water Purification written by Sabu Thomas and published by Elsevier. This book was released on 2018-11-14 with total page 892 pages. Available in PDF, EPUB and Kindle. Book excerpt: Novel nanoscale materials are now an essential part of meeting the current and future needs for clean water, and are at the heart of the development of novel technologies to desalinate water. The unique properties of nanomaterials and their convergence with current treatment technologies present great opportunities to revolutionize water and wastewater treatment. Nanoscale Materials for Water Purification brings together sustainable solutions using novel nanomaterials to alleviate the physical effects of water scarcity. This book covers a wide range of nanomaterials, including noble metal nanoparticles, magnetic nanoparticles, dendrimers, bioactive nanoparticles, polysaccharidebased nanoparticles, nanocatalysts, and redox nanoparticles for water purification. Significant properties and characterization methods of nanomaterials such as surface morphology, mechanical properties, and adsorption capacities are also investigated - Explains how the unique properties of a range of nanomaterials makes them important water purification agents - Shows how the use of nanotechnology can help create cheaper, more reliable, less energy-intensive, more environmentally friendly water purification techniques - Includes case studies to show how nanotechnology has successfully been integrated into water purification system design
Download or read book Heterogeneous Photocatalysis written by Mario J. Muñoz-Batista and published by Springer Nature. This book was released on 2020-07-01 with total page 301 pages. Available in PDF, EPUB and Kindle. Book excerpt: The series Topics in Current Chemistry Collections presents critical reviews from the journal Topics in Current Chemistry organized in topical volumes. The scope of coverage is all areas of chemical science including the interfaces with related disciplines such as biology, medicine and materials science. The goal of each thematic volume is to give the non-specialist reader, whether in academia or industry, a comprehensive insight into an area where new research is emerging which is of interest to a larger scientific audience. Each review within the volume critically surveys one aspect of that topic and places it within the context of the volume as a whole. The most significant developments of the last 5 to 10 years are presented using selected examples to illustrate the principles discussed. The coverage is not intended to be an exhaustive summary of the field or include large quantities of data, but should rather be conceptual, concentrating on the methodological thinking that will allow the non-specialist reader to understand the information presented. Contributions also offer an outlook on potential future developments in the field. The chapter "Mechanochemical Forces as a Synthetic Tool for Zero and One-Dimensional Titanium Oxide-Based Nano-photocatalysts" is available open access under a CC BY 4.0 License via link.springer.com.
Download or read book Green Photo active Nanomaterials written by Nurxat Nuraje and published by Royal Society of Chemistry. This book was released on 2015-11-06 with total page 433 pages. Available in PDF, EPUB and Kindle. Book excerpt: Providing up-to-date coverage of green nanomaterials and systems, this book provides comprehensive information on nanostructured materials, including their applications in energy and environmental sciences. The book focusses on photo-active nanostructured materials, from the basic understanding of solar energy activation to their sustainable preparation and applications in environmental remediation and fuel production from biomass and carbon dioxide. It also examines the health and environmental impacts of photo-catalyst nanomaterials. This book is an important reference for researchers and industrial chemists working in the fields of energy and environmental remediation.
Download or read book Homogeneous and Heterogeneous Photocatalysis written by E. PELIZZETTI and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 720 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ever since the oil crisis of 1973, researchers in various fields of chemistry have proposed various schemes to conserve energy, as well to convert the sun's abundant and limitless supply of energy to produce chemical fuels (e. g. , hydrogen from water, . •. ). The enthusiasm had no previous parallel in the mid-1970's. Unfortunately, despite the several good proposals, the results have proven - in retrospect - somewhat disappointing from an economic viable point of view. The reasons for the meagre results are manyfold not the least of which are the experimental difficulties encountered in storage systems. Moreover, the lack of a concerted, well orchestrated interdisciplinary approach has been significant. By contrast, the chemical advances made in the understanding of the processes involved in such schemes have been phenomenal. A recent book on this issue ( M. Gratzel, Energy Resources through Photochemistry and Catalysis, 1983) is witness to the various efforts and approaches taken by researchers. In the recent years, many more groups have joined in these efforts, and the number of papers in the lit~rature is staggering ! One of the motives for organizing this NATO Advanced Research Workshop stemmed from our view that it was time to take stock of the accomplishments and rather than propose new schemes, it was time to consider seriously avenues that are most promising.
Download or read book Visible Light Active Photocatalysis written by Srabanti Ghosh and published by John Wiley & Sons. This book was released on 2018-06-11 with total page 624 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive and timely overview of this important and hot topic, with special emphasis placed on environmental applications and the potential for solar light harvesting. Following introductory chapters on environmental photocatalysis, water splitting, and applications in synthetic chemistry, further chapters focus on the synthesis and design of photocatalysts, solar energy conversion, and such environmental aspects as the removal of water pollutants, photocatalytic conversion of CO2. Besides metal oxide-based photocatalysts, the authors cover other relevant material classes including carbon-based nanomaterials and novel hybrid materials. Chapters on mechanistic aspects, computational modeling of photocatalysis and Challenges and perspectives of solar reactor design for industrial applications complete this unique survey of the subject. With its in-depth discussions ranging from a comprehensive understanding to the engineering of materials and applied devices, this is an invaluable resource for a range of disciplines.
Download or read book Characterisation and Reactivity of Thermal and Photo assisted Charge Transfer Processes in TiO2 written by Charles Jenkins and published by . This book was released on 1998 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 692 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Transition Metal Oxides MxOy M written by Junzhe Dong and published by . This book was released on 2019 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: n the past few decades, transition metal oxides (TMO) show various unique properties and wide applications due to their electronic configuration and multiple possible structures. Among different TMO, titanium dioxide (TiO2), tungsten trioxide(WO3), and zinc oxide (ZnO) are most commonly oxides used as catalyst, sensors and electric devices due to their unique physical and chemical properties. Electrochemical anodization is a facile and cost-effective way to produce 1D self-assembly metal oxides,which integrates the advantage of larger surface area, short diffusion path, low quantum confinement, high charge transfer efficiency and tunable electronic structures. Post-annealing is a possible way to rearrange the disordered atomic arrangement of the anodic oxides and tune their electronic structure. In addition, the decoration of the anodic oxides with metal nanoparticles is another efficient way to modify the as-synthesized anodic oxides, which helps supress the recombination of the photogenerated charge carriers and prolong their life time. The as-prepared and modified anodic metal oxides exhibit various applications, including the photocatalyst, electrochemical catalyst and SERS substrates.The pre-treatment of the Ti substrate and electrolyte were conducted before formal anodization. Their influence on the morphology and mechanical properties of the anodic TiO2 were discussed. The results indicated that the regular TiO2 NTs with the hierarchical shape was produced on the patterned Ti substrate prepared by two-step anodization. Although the regularity of TiO2 NTs improved a lot with the increase of aging time, the pore size decreased as well as the surface homogeneity. The nanohardness and reduced modulus showed the obvious increase with the aging time and highest adhesion between TiO2 and Ti substrate was achieved by anodizing in the 25 h aging electrolyte. Anodic TiO2 initially has an amorphous structure and crystallizes into anatase after thermal annealing. High resolution transmission electron microscopy and in situ synchrotron X-ray diffraction were employed to study the dynamic phase transformation process and the effect of annealing parameters on the atomic structure. At temperatures above 330°C the crystallization process began immediately and ceased within ~500 s. The material was not fully crystallized (crystallinity only ~70 wt.%), even when the annealing time was prolonged to 7000 s at an elevated temperature. The incomplete crystallization could be ascribed to the effect of grain boundaries, oxygen vacancies, and fluorine ions. Besides the phase structure change of anodic TiO2 after annealing, the electric resistivity and wettability of the TiO2 were found to have a close relationship with the post heat treatment. The as-synthesized and annealed TiO2 were used as the electroplating substrate for fabrication Ni-TiO2 nanocomposite. The results reveal that the deposited Ni grows inside the nanotube on annealed TiO2 substrate, while it only forms a compact layer on the top of as-anodized. The resultant Ni-TiO2 nanocomposite on annealed TiO2 substrates also exhibited better oxygen evolution performance than on amorphous substrates in terms of low overpotential at a current density of 10 mA/cm2 and small Tafel slope. The modification of TiO2 can also be achieved by a novel technique that combines magnetron sputtering and thermal dewetting. The obtained Cu-TiO2 nanocomposite catalyst exhibited 4-fold increase in the photodegradation rate of methylene blue aqueous solution under solar light irradiation than anatase TiO2 prepared with sameanodization conditions. The enhanced photocatalytic activity was attributed to thesynergistic effect of Schottky barrier and surface plasmon resonance.Similar to anodic TiO2, regular self-organized nanoporous WO3 was prepared through anodization in the electrolyte containing ethylene glycol, ammonium fluoride and DI water, which was subsequently used as a template for deposition of Ag nanoparticles by magnetron sputtering and thermal dewetting. The synthesized Ag-WO3 nanocomosites showed large SERS enhancement factor of ~2.1× 107 and a low detection limit of ~1× 10-6 M Rhodamine B. The visible light responding behaviour of WO3, synergistic interaction between Ag nanoparticles and the WO3 substrate, and the plasmonic behaviour of Ag collectively contribute to the enhanced Raman scattering. Although TiO2 nanotube and WO3 nanoporous structure can be successfully prepared in the ethylene glycol electrolyte containing the NH4F, it did not work for anodic ZnO. A new type of self-assembled Zinc oxide (ZnO) nanostructure has been prepared by electrochemical anodization of Zinc foil in NaOH aqueous electrolyte. The experimental results indicate that the primary factor affecting anodic nanostructure is the applied voltage, while anodization time and electrolyte concentration also play significant roles in tailoring nanorod morphology.
