Synthesis and Characterization of Transition Metal Based Metal Oxide and Metallic Nanocrystals for AC Magnetic Devices and Catalysis

Synthesis and Characterization of Transition Metal Based Metal Oxide and Metallic Nanocrystals for AC Magnetic Devices and Catalysis PDF Author: Hongseok Yun
Publisher:
ISBN:
Category :
Languages : en
Pages : 378

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Book Description
The d-block elements are very important in magnetics, electronics, catalysis, and biological systems. The synthesis and characterization of nearly monodisperse d-block element based nanocrystals with a precise control over the size, composition, and shape are important to utilize the nanocrystals in such applications. The goals of my thesis are to synthesize d-block transition metal based nanocrystals and understand their magnetic and catalytic properties. I present the size- and composition-dependent AC magnetic permeability of superparamagnetic iron oxide nanocrystals for radio frequency applications. The nanocrystals are synthesized through high-temperature solvothermal decomposition, and their stoichiometry is determined by Mössbauer spectroscopy. Size-dependent magnetic permeability is observed in maghemite nanocrystals, while as-synthesized, magnetite-rich, iron oxide nanocrystals do not show size dependence due to the inhomogeneous crystal structure of the as-synthesized nanocrystals. The saturation magnetization of iron oxide nanocrystals is increased by doping of non-magnetic Zn2+ into A site of ferrite, resulting the enhancement of the real part of the magnetic permeability of Zn0.25Fe2.75O4 nanocrystals by twofold compared to that of similarly sized ferrite nanocrystals. The integration of 12.3 nm Zn0.25Fe2.75O4 nanocrystals into a microfabricated toroidal inductor and a solenoid inductor yield higher quality factors than air core inductors with the same geometries. The ligand exchange with dendrimers reduces the blocking temperature of Mn0.08Zn0.33Fe2.59O4 nanocrystal, indicating the decrease of dipolar coupling between nanocrystals. The study on MnxFe3-xO4 and CoxFe3-xO4 nanocrystals shows a clear difference in DC and AC magnetic behaviors of soft and hard magnetic nanocrystals. The inductor with zinc ferrite nanocrystal core is embedded into a power converter and its temperature dependent energy efficiency is measured. The energy efficiency of a power converter with the nanocrystal core inductor rises as the temperature increases while that of the power converters with an air core inductor or commercial core inductor decreases. Finally, I describe the hydrodeoxygenation reaction of 5-hydroxymethylfurfural into 2,5-dimethylfuran by metallic nanocrystals such as Pt, PtMn, PtFe, PtCo, and PtNi. Both conversion ratio and selectivity for 2,5-dimethylfuran show clear composition dependent catalytic properties and, in particular, 3.7 nm Pt3Co2 nanocrystals achieve 98 % of selectivity for 2,5-dimethylfuran.

Synthesis and Characterization of Transition Metal Based Metal Oxide and Metallic Nanocrystals for AC Magnetic Devices and Catalysis

Synthesis and Characterization of Transition Metal Based Metal Oxide and Metallic Nanocrystals for AC Magnetic Devices and Catalysis PDF Author: Hongseok Yun
Publisher:
ISBN:
Category :
Languages : en
Pages : 378

Get Book Here

Book Description
The d-block elements are very important in magnetics, electronics, catalysis, and biological systems. The synthesis and characterization of nearly monodisperse d-block element based nanocrystals with a precise control over the size, composition, and shape are important to utilize the nanocrystals in such applications. The goals of my thesis are to synthesize d-block transition metal based nanocrystals and understand their magnetic and catalytic properties. I present the size- and composition-dependent AC magnetic permeability of superparamagnetic iron oxide nanocrystals for radio frequency applications. The nanocrystals are synthesized through high-temperature solvothermal decomposition, and their stoichiometry is determined by Mössbauer spectroscopy. Size-dependent magnetic permeability is observed in maghemite nanocrystals, while as-synthesized, magnetite-rich, iron oxide nanocrystals do not show size dependence due to the inhomogeneous crystal structure of the as-synthesized nanocrystals. The saturation magnetization of iron oxide nanocrystals is increased by doping of non-magnetic Zn2+ into A site of ferrite, resulting the enhancement of the real part of the magnetic permeability of Zn0.25Fe2.75O4 nanocrystals by twofold compared to that of similarly sized ferrite nanocrystals. The integration of 12.3 nm Zn0.25Fe2.75O4 nanocrystals into a microfabricated toroidal inductor and a solenoid inductor yield higher quality factors than air core inductors with the same geometries. The ligand exchange with dendrimers reduces the blocking temperature of Mn0.08Zn0.33Fe2.59O4 nanocrystal, indicating the decrease of dipolar coupling between nanocrystals. The study on MnxFe3-xO4 and CoxFe3-xO4 nanocrystals shows a clear difference in DC and AC magnetic behaviors of soft and hard magnetic nanocrystals. The inductor with zinc ferrite nanocrystal core is embedded into a power converter and its temperature dependent energy efficiency is measured. The energy efficiency of a power converter with the nanocrystal core inductor rises as the temperature increases while that of the power converters with an air core inductor or commercial core inductor decreases. Finally, I describe the hydrodeoxygenation reaction of 5-hydroxymethylfurfural into 2,5-dimethylfuran by metallic nanocrystals such as Pt, PtMn, PtFe, PtCo, and PtNi. Both conversion ratio and selectivity for 2,5-dimethylfuran show clear composition dependent catalytic properties and, in particular, 3.7 nm Pt3Co2 nanocrystals achieve 98 % of selectivity for 2,5-dimethylfuran.

Synthesis and Characterization of Transition-metal Nanocrystals and Their Application in Catalysis

Synthesis and Characterization of Transition-metal Nanocrystals and Their Application in Catalysis PDF Author: Guangjun Cheng
Publisher:
ISBN:
Category :
Languages : en
Pages : 488

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Book Description


Chemically Deposited Nanocrystalline Metal Oxide Thin Films

Chemically Deposited Nanocrystalline Metal Oxide Thin Films PDF Author: Fabian I. Ezema
Publisher: Springer Nature
ISBN: 3030684628
Category : Technology & Engineering
Languages : en
Pages : 926

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Book Description
This book guides beginners in the areas of thin film preparation, characterization, and device making, while providing insight into these areas for experts. As chemically deposited metal oxides are currently gaining attention in development of devices such as solar cells, supercapacitors, batteries, sensors, etc., the book illustrates how the chemical deposition route is emerging as a relatively inexpensive, simple, and convenient solution for large area deposition. The advancement in the nanostructured materials for the development of devices is fully discussed.

Synthesis, Properties, and Applications of Oxide Nanomaterials

Synthesis, Properties, and Applications of Oxide Nanomaterials PDF Author: José A. Rodriguez
Publisher: John Wiley & Sons
ISBN: 0470108967
Category : Technology & Engineering
Languages : en
Pages : 640

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Book Description
Current oxide nanomaterials knowledge to draw from and build on Synthesis, Properties, and Applications of Oxide Nanomaterials summarizes the existing knowledge in oxide-based materials research. It gives researchers one comprehensive resource that consolidates general theoretical knowledge alongside practical applications. Organized by topic for easy access, this reference: * Covers the fundamental science, synthesis, characterization, physicochemical properties, and applications of oxide nanomaterials * Explains the fundamental aspects (quantum-mechanical and thermodynamic) that determine the behavior and growth mode of nanostructured oxides * Examines synthetic procedures using top-down and bottom-up fabrication technologies involving liquid-solid or gas-solid transformations * Discusses the sophisticated experimental techniques and state-of-the-art theory used to characterize the structural and electronic properties of nanostructured oxides * Describes applications such as sorbents, sensors, ceramic materials, electrochemical and photochemical devices, and catalysts for reducing environmental pollution, transforming hydrocarbons, and producing hydrogen With its combination of theory and real-world applications plus extensive bibliographic references, Synthesis, Properties, and Applications of Oxide Nanomaterials consolidates a wealth of current, complex information in one volume for practicing chemists, physicists, and materials scientists, and for engineers and researchers in government, industry, and academia. It's also an outstanding reference for graduate students in chemistry, chemical engineering, physics, and materials science.

Metal Nanoparticles for Catalysis

Metal Nanoparticles for Catalysis PDF Author: Franklin Tao
Publisher: Royal Society of Chemistry
ISBN: 1782621032
Category : Technology & Engineering
Languages : en
Pages : 285

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Book Description
Catalysis is a central topic in chemical transformation and energy conversion. Thanks to the spectacular achievements of colloidal chemistry and the synthesis of nanomaterials over the last two decades, there have also been significant advances in nanoparticle catalysis. Catalysis on different metal nanostructures with well-defined structures and composition has been extensively studied. Metal nanocrystals synthesized with colloidal chemistry exhibit different catalytic performances in contrast to metal nanoparticles prepared with impregnation or deposition precipitation. Additionally, theoretical approaches in predicting catalysis performance and understanding catalytic mechanism on these metal nanocatalysts have made significant progress. Metal Nanoparticles for Catalysis is a comprehensive text on catalysis on Nanoparticles, looking at both their synthesis and applications. Chapter topics include nanoreactor catalysis; Pd nanoparticles in C-C coupling reactions; metal salt-based gold nanocatalysts; theoretical insights into metal nanocatalysts; and nanoparticle mediated clock reaction. This book bridges the gap between nanomaterials synthesis and characterization, and catalysis. As such, this text will be a valuable resource for postgraduate students and researchers in these exciting fields.

Magnetic Oxides and Composites II

Magnetic Oxides and Composites II PDF Author: Rajshree B. Jotania
Publisher: Materials Research Forum LLC
ISBN: 1644900971
Category : Technology & Engineering
Languages : en
Pages : 270

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Book Description
Magnetic oxides have highly interesting applications in the fields of permanent magnets, microwave devices, magnetic refrigeration, sensors, catalysis, and the health sector. This book focuses on the synthesis, characterization, and applications of various perovskites, garnets, manganites, carbon-based metal oxide nanocomposites, nanoferrites, and graphene-metal oxide nanocomposites. Keywords: Magnetic Oxides, Permanent Magnets, Microwave Devices, Magnetic Refrigeration, Sensors, Catalysis, Perovskites, Nanoferrites, Manganites, Rare Earth Iron Garnet, Graphene-Metal Oxide Nanocomposites, Carbon Nanomaterials, Mesoporous Materials, Nanocatalysts, Multifunctional Ferrites, Magnetocaloric Effect, Biosynthesis, Photo Catalysis, Antibacterial Activity, High Density Recording Media.

Colloidal Metal Oxide Nanoparticles

Colloidal Metal Oxide Nanoparticles PDF Author:
Publisher: Elsevier
ISBN: 0128133589
Category : Technology & Engineering
Languages : en
Pages : 612

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Book Description
Colloidal Metal Oxide Nanoparticles: Synthesis, Characterization and Applications is a one-stop reference for anyone with an interest in the fundamentals, synthesis and applications of this interesting materials system. The book presents a simple, effective and detailed discussion on colloidal metal oxide nanoparticles. It begins with a general introduction of colloidal metal oxide nanoparticles, then delves into the most relevant synthesis pathways, stabilization procedures, and synthesis and characterization techniques. Final sections discuss promising applications, including bioimaging, biosensing, diagnostic, and energy applications—i.e., solar cells, supercapacitors and environment applications—i.e., the treatment of contaminated soil, water purification and waste remediation. - Provides the most comprehensive resource on the topic, from fundamentals, to synthesis and characterization techniques - Presents key applications, including biomedical, energy, electronic and environmental - Discusses the most relevant techniques for synthesis, patterning and characterization

Design, Synthesis, and Characterization of Transition Metal Oxide Based Functional Materials for Multi-phase Catalytic Applications

Design, Synthesis, and Characterization of Transition Metal Oxide Based Functional Materials for Multi-phase Catalytic Applications PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 276

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Book Description


Metal Oxide Nanoparticles in Organic Solvents

Metal Oxide Nanoparticles in Organic Solvents PDF Author: Markus Niederberger
Publisher: Springer Science & Business Media
ISBN: 1848826710
Category : Science
Languages : en
Pages : 223

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Book Description
Metal Oxide Nanoparticles in Organic Solvents discusses recent advances in the chemistry involved for the controlled synthesis and assembly of metal oxide nanoparticles, the characterizations required by such nanoobjects, and their size and shape depending properties. In the last few years, a valuable alternative to the well-known aqueous sol-gel processes was developed in the form of nonaqueous solution routes. Metal Oxide Nanoparticles in Organic Solvents reviews and compares surfactant- and solvent-controlled routes, as well as providing an overview of techniques for the characterization of metal oxide nanoparticles, crystallization pathways, the physical properties of metal oxide nanoparticles, their applications in diverse fields of technology, and their assembly into larger nano- and mesostructures. Researchers and postgraduates in the fields of nanomaterials and sol-gel chemistry will appreciate this book’s informative approach to chemical formation mechanisms in relation to metal oxides.

Metal Oxide Nanostructures

Metal Oxide Nanostructures PDF Author: Daniela Nunes
Publisher: Elsevier
ISBN: 012811505X
Category : Technology & Engineering
Languages : en
Pages : 331

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Book Description
Metal Oxide Nanostructures: Synthesis, Properties and Applications covers the theoretical and experimental aspects related to design, synthesis, fabrication, processing, structural, morphological, optical and electronic properties on the topic. In addition, it reviews surface functionalization and hybrid materials, focusing on the advantages of these oxide nanostructures. The book concludes with the current and future prospective applications of these materials. Users will find a complete overview of all the important topics related to oxide nanostructures, from the physics of the materials, to its application. - Delves into hybrid structured metal oxides and their promising use in the next generation of electronic devices - Includes fundamental chapters on synthesis design and the properties of metal oxide nanostructures - Provides an in-depth overview of novel applications, including chromogenics, electronics and energy