Download Free Preparation And Characterization Of Stable Macroporous Titania Nano Wells Book in PDF and EPUB Free Download. You can read online Preparation And Characterization Of Stable Macroporous Titania Nano Wells and write the review.

Silica based sol-gel thin films have been extensively studied because of their advantages that include optical transparency, high biodegradability and low intrinsic fluorescence. However, one concern with silica based sol-gel derived materials is their long term stability in aqueous solutions. Another concern is their limited porosity. These two concerns limit the application of these materials in catalysis and separations. The main objective of this study is to prepare porous, thin films using titanium alkoxides as precursors and evaluate their long term stability in aqueous solutions. Colloidal crystal templating will be used to introduce macrosized pores into the titania network. The materials will be characterized using SEM and AFM. To prove that the templated films provide access to the underlying surface of the electrode, a conducting metal like copper was electrodeposited inside the nano-wells. The stability of titania and silica films will be evaluated over a two month period using cyclic voltammetry with three redox probes.
Doctoral Thesis / Dissertation from the year 2011 in the subject Chemistry - Materials Chemistry, East China University of Science and Technology (-), language: English, abstract: Considerable effort has been made to design, fabricate, and manipulate nanostructured materials by innovative approaches. The precise control of nanoscale structures will pave the way not only for elucidating unique size/shape dependent physicochemical properties but also for realizing new applications in science and technology. Nanotechnology offers unprecedented opportunities for improving our daily lives and the environment in which we live. This thesis mainly describes recent progress in the design, fabrication, and modification of nanostructured semiconductor materials for environmental applications. The scope of this thesis covers TiO2, Bi2O3 and BiOCl materials, focusing particularly on TiO2-based nanostructures (e.g., pure, doped, coupled, mesoporous, hierarchically porous, and ordered mesoporous TiO2). Mesoporous titania is of particular interest since this class of materials possesses well-defined porosity and large specific surface areas. For photocatalytic degradation of organics, these desirable properties are anticipated to improve the efficiency. So in the first part of work, I have synthesized the mesoporous titania by using poly ethylene glycol as a template in dilute acetic acid aqueous solution by hydrothermal process and investigated the effect of PEG molecular weights and thermal treatment on the resultant structure and photocatalytic activity. When the molecular weights of PEG vary from 600 to 20,000, the particle sizes of mesoporous-TiO2 structure decrease from 15.1 to 13.3 nm and mean pore sizes increase from 6.9-10.6 nm. The activities of these mesoporous-TiO2 photocatalysts prepared by using PEG are evaluated and compared with Degussa P-25 using chloro-phenol as a testing compound. [...]
Titania nanofibers were fabricated using electrospinning and characterized using SEM, XRD and TEM for morphology, chemistry and crystalline structures. The prepared titania nanofibers were approximately 20 nm in diameter and consisted of anatase phased crystalline grains having sizes of ~10 nm. Different spin dopes were prepared by varying the ratio of N, N=dimethylformamide (DME) to isopropanol (IPA). The results indicated that the precursive nanofibers and the final TiO2 nanofibers made from the spin dopes containing DMF alone or DMF/isopropanol mixture as the solvent had the common cylindrical morphology with diameters ranging from tens to hundreds of nanometers, while those made from the spin dope containing isopropanol alone as the solvent had the abnormal concave morphology with sizes/ widths ranging from sub-microns to microns. Electrospun titania nanofibers as well as a commercial titania powder were used to prepare aluminum/titania composites using friction stir processing, and the morphological structures of the composites were characterized using TEM. The interaction of the aluminum matrix with nanofibers was found to be stronger than powder in the aluminum matrix. Comparison of microhardness measurement of the titania nanofibers/aluminum composite with titania power/aluminum composite indicated that the hardness increment is higher with nanofibers than powder. The photocatalytic efficiency of electrospun titania nanofibers is compared with that of commercial titania sample (Degussa P 25) for the degradation of Rhodamine B. The degradation rate of Rhodamine B after 15 min irradiation is identical for both the catalysts.
This thesis focuses on porous monolithic materials that are not in the forms of particles, fibers, or films. In particular, the synthetic strategy of porous monolithic materials via the sol–gel method accompanied by phase separation, which is characterized as the non-templating method for tailoring well-defined macropores, is described from the basics to actual synthesis. Porous materials are attracting more and more attention in various fields such as electronics, energy storage, catalysis, sensing, adsorbents, biomedical science, and separation science. To date, many efforts have been made to synthesize porous materials in various chemical compositions—organics, inorganics including metals, glasses and ceramics, and organic-inorganic hybrids. Also demonstrated in this thesis are the potential applications of synthesized porous monolithic materials to separation media as well as to electrodes for electric double-layer capacitors (EDLCs) and Li-ion batteries (LIBs). This work is ideal for graduate students in materials science and is also useful to engineers or scientists seeking basic knowledge of porous monolithic materials.
This comprehensive three-volume handbook brings together a review of the current state together with the latest developments in sol-gel technology to put forward new ideas. The first volume, dedicated to synthesis and shaping, gives an in-depth overview of the wet-chemical processes that constitute the core of the sol-gel method and presents the various pathways for the successful synthesis of inorganic and hybrid organic-inorganic materials, bio- and bio-inspired materials, powders, particles and fibers as well as sol-gel derived thin films, coatings and surfaces. The second volume deals with the mechanical, optical, electrical and magnetic properties of sol-gel derived materials and the methods for their characterization such as diffraction methods and nuclear magnetic resonance, infrared and Raman spectroscopies. The third volume concentrates on the various applications in the fields of membrane science, catalysis, energy research, biomaterials science, biomedicine, photonics and electronics.
This thesis investigated different aspects of the structural chemistry of titanium oxide powders and in particular how doping effects the anatase to rutile phase transition. Chapter 1 gives a summary of the solid state chemistry of titanium dioxide. It also presents some analysis of the main commercial roles and developing fields where titanium oxide has found a use. It summarises the two main crystalline forms used within industry, i.e. the metastable anatase phase and the more stable rutile phase. A synopsis of sol-gel techniques suitable for titania production is also discussed as well as a brief introduction into the development of mesoporous molecules. Chapter II describes and introduces the various analytical techniques used during this investigation of titanium oxide materials. These included powder x-ray diffraction (PXRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), BET surface analysis via nitrogen adsorption and differential thermal analysis (DTA). Chapter III describes the sol-gel synthesis of titania doped with 0-30% Zr and the effects the dopant levels have on the properties of titania. This involves monitoring the anatase to rutile transformation temperature with respect to additive concentration, measurement of the relative weight fractions of both phases versus temperature, analysis of the crystallite size for both polymorphs of titania at different temperatures, determination of the activation energy for anatase to rutile conversion via the use of Arrhenius plots, DTA analysis and microstructure analysis via scanning electron microscopy. PXRD was also used to investigate the solubility of zirconia in the rutile phase as well as the appearance of any oxide phases involving zirconium, titanium and oxygen at elevated temperatures. Chapter IV details the effects of a 1% dopant level into Ti02 using Al, Si, Mn, Co, and V as additives on the properties of titania. The synthesis of these materials is also described and the properties investigated include:- phase transition temperatures, crystallite sizes, weight fractions, microstructure and activation energies for anatase to rutile conversion. Chapter V discusses the synthesis of mixed oxide doped titania and the influence mixed additives exhibit on the properties of titania when compared to single additives within a temperature range of 200-1100oC. The two mixed oxide dopant systems investigated here were 5%Zr5%Si and 5%Zr5%Al. Chapter VI details the different synthesis techniques attempted, i.e. sol-gel and pseudo sol-gel methods, to produce pure mesoporous undoped titania. A synthesis method for 5%Zr5%Si doped mesoporous titania is aldo described. Characterizatin of these materials via low angle powder x-ray diffraction (PXRD) and BET nitrogen adsorption studies is also discussed.
Design, Fabrication, and Characterization of Multifunctional Nanomaterials covers major techniques for the design, synthesis, and development of multifunctional nanomaterials. The chapters highlight the main characterization techniques, including X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, energy dispersive X-ray spectroscopy, and scanning probe microscopy.The book explores major synthesis methods and functional studies, including: Brillouin spectroscopy; Temperature-dependent Raman spectroscopic studies; Magnetic, ferroelectric, and magneto-electric coupling analysis; Organ-on-a-chip methods for testing nanomaterials; Magnetron sputtering techniques; Pulsed laser deposition techniques; Positron annihilation spectroscopy to prove defects in nanomaterials; Electroanalytic techniques. This is an important reference source for materials science students, scientists, and engineers who are looking to increase their understanding of design and fabrication techniques for a range of multifunctional nanomaterials. Explains the major design and fabrication techniques and processes for a range of multifunctional nanomaterials; Demonstrates the design and development of magnetic, ferroelectric, multiferroic, and carbon nanomaterials for electronic applications, energy generation, and storage; Green synthesis techniques and the development of nanofibers and thin films are also emphasized.