Download or read book Synthesis and Characterization of Transition Metal Nitride and Selenide Nanocrystals and Heterostructures written by Robert William Lord and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The properties of nanomaterials are intimately dependent on their size, morphology, composition both elemental and structural, as well as their crystal structure or atomic arrangement. There exists a fundamental need to develop methods to precisely control and tune these parameters in order to target desirable materials. Colloidal chemistries utilize wet chemical precursors to synthesize inorganic nanomaterials from the bottom up and produce high quality materials. In addition to single component material synthesis, colloidal chemistries have been developed to synthesize multicomponent nanomaterials systems through a process called seeded growth. Seeded growth utilizes preformed nanoparticles as substrates to nucleate and grow new materials from their surfaces. This has led to the synthesis of highly complex heterostructured nanoparticles which allow for the incorporation of multiple material properties within single particle frameworks. While these techniques can control the structure and composition of the synthesized material, they do not allow for as much control over the resulting crystal structure. Other methods have been developed which allow for crystallographic templating and compositional modulation by post-synthetic cation exchange. Cation exchange utilizes molecular agents to solvate and exchange host cations in preformed crystals with those in solution while maintaining the anion sublattice relatively unperturbed. The crystallographic symmetry of the anion sublattice determines the symmetry of the final product phase. As such, cation exchange has allowed researchers to synthesize materials which are either metastable in bulk or not easily assessable through other methods. In this dissertation I discuss my efforts to utilize these synthetic tools to synthesize new and complex inorganic nanoparticles. First, I describe the seeded growth of Cu3N and Cu3PdN on Pt and Au nanocrystals. Utilizing Pt-Cu3PdN as the model system, it was observed that Cu3PdN nucleated and grew in a step-wise pathway with the initial deposition of Cu onto the surface. This was followed by the deposition of Pd onto the corners and edges of the Pt nanocubes which was followed by the coalescence and crystallization of Cu with the Pd to ultimately give Cu3PdN. When nucleating on more faceted or spherical seeds, whether Pt or Au, the resulting heterostructures took on more core@shell structures. In the absence of Pd, Cu3N nucleates indiscriminately on the surface of Pt without any of the regioselectivity seen with Cu3PdN. When utilizing Au seeds, AuCu alloy formation is observed without any apparent heterostructure formation. These observations helped us develop guidelines which are anticipated to be applicable to the formation of other ternary nitride heterostructures. Second, I discuss the synthesis of a new, metastable phase of copper selenide nanoparticles. This material was shown by EDS and XPS to adopt a nominally 2:1 stoichiometry and the XRD pattern did not match any known phase of Cu2-xSe. However, the nanoparticles did adopt a crystal structure similar to previously observed weissite Cu2-xTe. A structural model for our Cu2-xSe phase was developed utilizing a recently reported structural model for weissite Cu2-xTe which was computationally verified in collaboration with Professor Ismaila Dabo's group. Weissite-like Cu2-xSe has trigonal symmetry (space group P ̄3 m1) and is a layered structure with alternative Cu-rich and Cu-deficient layers sandwiched between layers of Se. UV-vis-NIR spectroscopy of weissite-like Cu2-xSe showed a broad plasmon absorbance band centered around 1550 nm. Lastly, I discuss my efforts to develop synthetic guidelines for the competitive synthesis of ternary copper selenide phases during their nucleation on Pt nanoparticle seeds. We showed experiments which allude to two potential synthetic pathways for the formation of CuFeSe2 and CuInSe2. It was observed that the CuInSe2 forms through a multistep pathway starting with the initial nucleation of Cu2-xSe followed by the incorporation of the In3+ through a high temperature cation exchange reaction. However, CuFeSe2 was shown to most likely to form by direct nucleation. The differences in these reactions were observed when their simultaneous nucleation was attempted, where only Pt--CuIn¬Se2 formed.

Download or read book Synthesis and Characterization of Transition Metal Nitride Materials written by Shalawn Kirkland Jackson and published by . This book was released on 2001 with total page 412 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis and Characterization of Transition Metal Nitrides and Carbides for Catalysis and Electrochemistry Application written by Sarah Metzke and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: It was the goal of this work to explore two different synthesis pathways using green chemistry. The first part of this thesis is focusing on the use of the urea-glass route towards single phase manganese nitride and manganese nitride/oxide nano-composites embedded in carbon, while the second part of the thesis is focusing on the use of the “saccharide route” (namely cellulose, sucrose, glucose and lignin) towards metal (Ni0), metal alloy (Pd0.9Ni0.1, Pd0.5Ni0.5, Fe0.5Ni0.5, Cu0.5Ni0.5 and W0.15Ni0.85) and ternary carbide (Mn0.75Fe2.25C) nanoparticles embedded in carbon. In the interest of battery application, MnN0.43 nanoparticles surrounded by a graphitic shell and embedded in carbon with a high surface area (79 m^2/g) were synthesized, following a previously set route.The comparison of the material characteristics before and after the discharge showed no remarkable difference in terms of composition and just slight differences in the morphological point of view, meaning the particles are stable but agglomerate. The graphitic shell ...

Download or read book Synthesis and Characterization of Transition metal Nanocrystals and Their Application in Catalysis written by Guangjun Cheng and published by . This book was released on 2003 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis and Characterization of New Transition Metal Nitrides written by Lev A. Sviridov and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis and Characterization of 2D Nanocrystals and Thin Films of Transition Metal Carbides MXenes written by and published by . This book was released on 2014 with total page 41 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Transition Metal Carbides and Nitrides MXenes Handbook written by Chuanfang Zhang and published by John Wiley & Sons. This book was released on 2024-07-23 with total page 788 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive overview of the synthesis of high-quality MXenes In Transition Metal Carbides and Nitrides (MXenes) Handbook: Synthesis, Processing, Properties and Applications, a team of esteemed researchers provides an expert review encompassing the fundamentals of precursor selection, MXene synthesis, characterizations, properties, processing, and applications. You’ll find detailed discussions of the selection of MXene members for specific applications, as along with summaries of the physical and chemical properties of MXenes, including electrical, mechanical, optical, electromechanical, electrochemical, and electromagnetic properties. The authors delve into both successful and unsuccessful synthesis examples, offering detailed explanations of various failures to facilitates a comprehensive understanding of the reasons behind unsuccessful syntheses. Additionally, they provide detailed examinations on the characterizations of MXenes, empowering readers to develop a sophisticated understanding of how to achieve optimal quality, flake size, oxidation states, and more. You’ll also find: A thorough review of common applications of MXenes, including electrochemical applications, electromagnetic interference shielding, communications devices, and more Comprehensive explorations of solution and non-solution processing of MXenes Practical discussions of the synthesis of high-quality MXene powders, colloidal solutions and flakes, including information about MXene precursors Fulsome treatments of MXene precursor selection and their impact on MXene quality Tailored to meet the needs of graduate students, researchers, and scientists in the areas of materials science, inorganic chemistry, and physical chemistry, the Transition Metal Carbides and Nitrides (MXenes) Handbook will also benefit biochemists and professionals working in drug delivery.

Download or read book Synthesis and Characterization of Transition Metal and Metal Oxide Nanoparticles Using Dendritic Complexes written by Elisabeta Mitran and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Preparation and Characterization of High Surface Area Transition Metal Nitrides written by Christopher Harold Jaggers and published by . This book was released on 1988 with total page 510 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis and Characterization of Colloidal Indium Nitride Nanocrystals and Study of Their Electronic Structure and Size and Shape Dependent Optical Properties written by Basudeb Chakraborty and published by . This book was released on 2014 with total page 105 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Neglected World written by Cristina Giordano and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Potentiality of nanosized materials has been largely proved but a closer look shows that a significant percentage of this research is related to oxides and metals, while the number drastically drops for metallic ceramics, namely transition metal nitrides and metal carbides. The lack of related publications do not reflect their potential but rather the difficulties related to their synthesis as dense and defect-free structures, fundamental prerequisites for advanced mechanical applications. The present habilitation work aims to close the gap between preparation and processing, indicating novel synthetic pathways for a simpler and sustainable synthesis of transition metal nitride (MN) and carbide (MC) based nanostructures and easier processing thereafter. In spite of simplicity and reliability, the designed synthetic processes allow the production of functional materials, with the demanded size and morphology. The goal was achieved exploiting classical and less-classical precursors, ranging from common metal salts and molecules (e.g. urea, gelatin, agar, etc), to more exotic materials, such as leafs, filter paper and even wood. It was found that the choice of precursors and reaction conditions makes it possible to control chemical composition (going for instance from metal oxides to metal oxy-nitrides to metal nitrides, or from metal nitrides to metal carbides, up to quaternary systems), size (from 5 to 50 nm) and morphology (going from mere spherical nanoparticles to rod-like shapes, fibers, layers, meso-porous and hierarchical structures, etc). The nature of the mixed precursors also allows the preparation of metal nitrides/carbides based nanocomposites, thus leading to multifunctional materials (e.g. MN/MC@C, MN/MC@PILs, etc) but also allowing dispersion in liquid media. Control over composition, size and morphology is obtained with simple adjustment of the main route, but also coupling it with processes such as electrospin, aerosol spray, bio-templating, etc. Last but not least, the nature of the precursor materials also allows easy processing, including printing, coating, casting, film and thin layers preparation, etc). The designed routes are, concept-wise, similar and they all start by building up a secondary metal ion-N/C precursor network, which converts, upon heat treatment, into an intermediate "glass". This glass stabilizes the nascent nanoparticles during their nucleation and impairs their uncontrolled growth during the heat treatment (scheme 1). This way, one of the main problems related to the synthesis of MN/MC, i.e. the need of very high temperature, could also be overcome (from up to 2000°C, for classical synthesis, down to 700°C in the present cases). The designed synthetic pathways are also conceived to allow usage of non-toxic compounds and to minimize (or even avoid) post-synthesis purification, still bringing to phase pure and well-defined (crystalline) nanoparticles. This research aids to simplify the preparation of MN/MC, making these systems now readily available in suitable amounts both for fundamental and applied science. The prepared systems have been tested (in some cases for the first time) in many different fields, e.g. battery (MnN0.43@C shown a capacity stabilized at a value of 230 mAh/g, with coulombic efficiencies close to 100%), as alternative magnetic materials (Fe3C nanoparticles were prepared with different size and therefore different magnetic behavior, superparamagnetic or ferromagnetic, showing a saturation magnetization value up to 130 emu/g, i.e. similar to the value expected for the bulk material), as filters and for the degradation of organic dyes (outmatching the performance of carbon), as catalysts (both as active phase but also as active support, leading to high turnover rate and, more interesting, to tunable selectivity). Furthermore, with this route, it was possible to prepare for the first time, to the best of our knowledge, well-defined and crystalline MnN0.43, Fe3C and Zn1.7GeN1.8O nanoparticles via bottom-up approaches. Once the synthesis of these materials can be made straightforward, any further modification, combination, manipulation, is in principle possible and new systems can be purposely conceived (e.g. hybrids, nanocomposites, ferrofluids, etc).zeige weniger

Download or read book Synthesis and Characterization of Nanocomposite Transition Metal Oxide Thin Films written by James T. Cahill and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis and Characterization of Two dimensional Transition Metal Dichalcogenides Alloys and Heterojunctions Over Various Substrates Via Chemical Vapor Deposition written by David Barroso and published by . This book was released on 2017 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt: Interest in two-dimensional (2D) electronic materials has exploded in the past decade, starting with the isolation of single layer graphene in 2004 by Novoselov. Similar to graphene, as a stable material in the single-layer, transition metal dichalcogenides (TMDs) further the advancement of 2D materials, but also provide an intrinsic transition to a direct bandgap in the single layer, thus giving these materials an advantage over graphene. Furthermore, TMDs have some of the highest notable Ion/Ioff ratios of other 2D materials, making them extremely favorable. However, none of these 2D materials can be used as a standalone for modern electronic applications, therefore, heterostructures of these materials must be created. An understanding of the way these materials are synthesized and ways to manipulate the synthesis is necessary to achieve such structures. Chemical vapor deposition (CVD) is a commonly used method to create single-layer TMDs among others such as mechanical exfoliation and metal sulfurization/selenization. Here I present facile methods by which to synthesize pristine, pure, 2D TMDs via CVD process manipulation. Additionally, in-situ operation of the CVD furnaces leads to the ability to alloy these materials and create heterostructures, leading to a study of tunable optical and physical properties. Last, I show the use of various/nanofabricated features on growth substrates in order to lead to a deeper understanding of the growth mechanisms for TMDs.

Download or read book Synthesis Nanocrystal Deposition and Characterization of 2D Transition Metal Trihalide Solid Solutions written by Samuel Froeschke and published by . This book was released on 2023* with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis and Characterization of New CN based Transition Metal Complexes written by Omar Mowafaq Younis Al-Ramadhani and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis and Characterization of Ordered Mesoporous Transition Metal Oxides and Nitrides written by Spencer William Robbins and published by . This book was released on 2015 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt: Controlling the structure of inorganic materials on the mesoscale (2-50 nm) is desirable for many applications and can influence the materials' properties and performance in devices. Amphiphilic block copolymers (BCPs) have been used extensively to structure-direct transition metal oxides, controlling their mesoscale morphology. By selectively incorporating metal oxide precursors into one block of the BCP and removing the BCP through thermal decomposition, ordered mesoporous metal oxides with well-defined mesoscale morphologies can be achieved that are interesting, e.g. for energy conversion and storage applications. This dissertation reports on the amphiphilic block terpolymer poly(isoprene)-blockpoly(styrene)-block-poly(ethylene oxide) used in combination with sol-gel metal oxide precursors to generate ordered three-dimensionally (3D) mesoporous metal oxides. 3D cocontinuous cubic network structures such as the alternating gyroid are particularly interesting for energy applications due to their chirality, co-continuity, and high porosity. In particular, the high porosity and mesoscale dimensions can facilitate rapid diffusion of gases/liquids, but limit solid state diffusion lengths in the inorganic structure during chemical conversions of the oxides, e.g. nitriding. Freestanding gyroidal mesoporous metal oxides can be further processed into gyroidal mesoporous metal nitrides by heating under flowing ammonia gas. Transition metal nitrides are of interest due to their electrical conductivity and electrochemical stability. The development of a synthesis for 3D ordered mesoporous nitrides opens paths for studying the effects of welldefined block copolymer mesostructures on superconductivity, an exciting new field.

Download or read book Synthesis and Characterization of Transition Metal Complexes of the Ligand DDDT 2 5 6 Dihydro l 4 dithiin 2 3 dithiolate written by Jane Alena Hanna Welch and published by . This book was released on 1989 with total page 570 pages. Available in PDF, EPUB and Kindle. Book excerpt: