Synthesis and Characterization of Two- and Three-dimensional Nanolaminated Carbides PDF Download

Author: Quanzheng Tao
Publisher:
ISBN: 9789179298791
Category :
Languages : en
Pages : 59

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Author: Andrejs Petruhins
Publisher: Linköping University Electronic Press
ISBN: 917685342X
Category :
Languages : en
Pages : 78

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MAX phases are a group of nanolaminated ternary carbides and nitrides, with a composition expressed by the general formula Mn+1AXn (?? = 1 ? 3), where M is a transition metal, A is an A-group element, and X is carbon and/or nitrogen. MAX phases have attracted interest due to their unique combination of metallic and ceramic properties, related to their inherently laminated structure of a transition metal carbide (Mn+1Xn) layer interleaved by an A-group metal layer. This Thesis explores synthesis and characterization of magnetic MAX phases, where the A-group element is gallium (Ga). Due to the low melting point of Ga (T = 30 °C), conventional thin film synthesis methods become challenging, as the material is in liquid form at typical process temperatures. Development of existing methods has therefore been investigated, for reliable/reproducible synthesis routes, including sputtering from a liquid target, and resulting high quality material. Routes for minimizing trial-and-error procedures during optimization of thin film synthesis have also been studied, allowing faster identification of optimal deposition conditions and a simplified transfer of essential deposition parameters between different deposition systems. A large part of this Thesis is devoted towards synthesis of MAX phase thin films in the Cr-Mn-Ga-C system. First, through process development, thin films of Cr2GaC were deposited by magnetron sputtering. The films were epitaxial, however with small amount of impurity phase Cr3Ga, as confirmed by X-ray diffraction (XRD) measurements. The film structure was confirmed by scanning transmission electron microscopy (STEM) and the composition by energy dispersive X-ray spectroscopy (EDX) inside the TEM. Inspired by predictive ab initio calculations, the new MAX phase Mn2GaC was successfully synthesized in thin film form by magnetron sputtering. Structural parameters and magnetic properties were analysed. The material was found to have two magnetic transitions in the temperature range 3 K to 750 K, with a first order transition at around 214 K, going from non-collinear antiferromagnetic state at lower temperature to an antiferromagnetic state at higher temperature. The Neél temperature was determined to be 507 K, changing from an antiferromagnetic to a paramagnetic state. Above 800 K, Mn2GaC decomposes. Furthermore, magnetostrictive, magnetoresistive and magnetocaloric properties of the material were iv determined, among which a drastic change in lattice parameters upon the first magnetic transition was observed. This may be of interest for magnetocaloric applications. Synthesis of both Cr2GaC and Mn2GaC in thin film form opens the possibility to tune the magnetic properties through a solid solution on the transition metal site, by alloying the aforementioned Cr2GaC with Mn, realizing (Cr1-xMnx)2GaC. From a compound target with a Cr:Mn ratio of 1:1, thin films of (Cr0.5Mn0.5)2GaC were synthesized, confirmed by TEM-EDX. Optimized structure was obtained by deposition on MgO substrates at a deposition temperature of 600 ºC. The thin films were phase pure and of high structural quality, allowing magnetic measurements. Using vibrating sample magnetometry (VSM), it was found that (Cr0.5Mn0.5)2GaC has a ferromagnetic component in the temperature range from 30 K to 300 K, with the measured magnetic moment at high field decreasing by increasing temperature. The remanent moment and coercive field is small, 0.036 ?B, and 12 mT at 30 K, respectively. Using ferromagnetic resonance spectroscopy, it was also found that the material has pure spin magnetism, as indicated by the determined spectroscopic splitting factor g = 2.00 and a negligible magnetocrystalline anisotropy energy. Fuelled by the recent discoveries of in-plane chemically ordered quaternary MAX phases, so called i-MAX phases, and guided by ab initio calculations, new members within this family, based on Cr and Mn, were synthesized by pressureless sintering methods, realizing (Cr2/3Sc1/3)2GaC and (Mn2/3Sc1/3)2GaC. Their structural properties were determined. Through these phases, the Mn content is the highest obtained in a bulk MAX phase to date. This work has further developed synthesis processes for sputtering from liquid material, for an optimized route to achieve thin films of controlled composition and a high structural quality. Furthermore, through this work, Mn has been added as a new element in the family of MAX phase elements. It has also been shown, that alloying with different content of Mn gives rise to varying magnetic properties in MAX phases. As a result of this Thesis, it is expected that the MAX phase family can be further expanded, with more members of new compositions and new properties.

Author: Ingemar Persson
Publisher: Linköping University Electronic Press
ISBN: 9176850854
Category :
Languages : en
Pages : 91

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Book Description
Research on two-dimensional (2D) materials is a rapidly growing field owing to the wide range of new interesting properties found in 2D structures that are vastly different from their three-dimensional (3D) analogues. In addition, 2D materials embodies a significant surface area that facilitates a high degree of surface reactions per unit volume or mass, that is imperative in many applications such as catalysis, energy storage, energy conversion, filtration, and single molecule sensing. MXenes constitute a family of 2D materials consisting of transition metal carbides and/or nitrides, which are typically formed after selective etching of their 3D parent MAX phases. The latter, are a family of nanolaminated compounds that typically follow the formula Mn+1AXn (n=1-3), where M is a transition metal, A is a group 13 or 14 element, and X is C and or N. Selective etching by aqueous F- containing acids removes the A layer leaving 2D Mn+1Xn slabs instantly terminated by a mix of O-, OH- and F-groups. The first and most investigated MXene is Ti3C2TX, where TX stands for surface termination, which has shown record properties in a range of applications (eg. electrode in Li-batteries, supercapacitors, sieving membrane, electromagnetic interference shielding, and carbon capture). Adding to that, over 30 different MXenes have been discovered since 2011, exhibiting alternative or superior properties. Most importantly, elegant routes for property design in the MXene family has been demonstrated, by means of either varying the chemistry in the Mn+1Xn compound, by alloying two M elements, or by changing the structure of the MXene by introducing vacancies. The present work has a led to an additional route for post synthesis property tuning in MXenes by manipulation of surface termination elements. This enables a unique toolbox for property tuning which is not available to other 2D materials and is highly beneficial for applications that is dependent on surface reactions. Furthermore, chemical and structural characterization of terminations on single sheets is essential to rule out the influence of intercalants or contamination that is typically present in multilayer MXene samples or thin films. For that purpose, a method for preparing isolated contamination free single sheets of MXene samples for transmission electron microscopy (TEM) characterization was established. In order to determine vacancy and termination sites, atomically resolved scanning (S)TEM imaging and image simulations was carried out. Two main processes were employed to substitute the termination elements. 1) An initial thermal treatment in vacuum facilitates F desorption and it was shown that O-terminations rearranges on the evacuated sites. H2 gas exposure in a controlled environment demonstrated a removal of the remaining O-terminations. As a result, termination-free MXene is possible to realize under vacuum conditions. 2) CO2 was introduced as a first non-inherent termination on MXene by in situ CO2 gas exposure at low temperatures. That was a first demonstration of Ti3C2TX as promising material for carbon capture. Additionally, O-saturated surfaces were demonstrated after introduction of O2 gas on the F-depleted Ti3C2TX MXene, which is highly relevant for hydrogen evolution reactions where fully O-terminated Ti3C2TX are predicted to improve efficiency. A Lewis acid melt synthesis method was used to realize the first MXene exclusively terminated with Cl. Moreover, this was the first report of a MXene directly synthesised with terminations other than O, OH, and F. Furthermore, we have expanded the space of property tuning by introduction of chemical ordering, by selective etching of Y in an alloyed (Mo2/3Y1/3)2CTX MXene. This either produced chemical ordering with one M (Mo) element and vacancies, or ordering between two M (Mo and Y) elements. This was further reported to significantly increase volumetric capacitance because of the increased number of active sites around vacancies, leading to an increasing charge density. As a final note, the stability of Nb2CTX MXene under ambient conditions was investigated. It was found that the surface Nb adatoms, present after etching, got oxidized over time which resulted in local clustering and effectively degraded the MXene. This work has demonstrated reproducible surface characterization methods for determining termination elements and sites in 2D MXenes, that is ultimately governing MXene properties. Most importantly, we report on a new approach for MXene property tuning as well as contributing to several existing property tuning approaches.

Author: Jay Singh
Publisher: John Wiley & Sons
ISBN: 1119874017
Category : Technology & Engineering
Languages : en
Pages : 389

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Book Description
MXenes One-stop reference explaining the manufacturing, design, and many applications of MXenes in an easy-to-understand linear format MXenes is a one-stop reference on MXenes, a promising new class of 2D materials, discussing the routes of functionalization and modifications towards high performance materials and providing broad coverage of lab synthesis methods. To aid in reader comprehension, this text presents the topic in a linear fashion, starting with an introduction to MXenes and ending with a comparison of MXenes to other similar 2D materials, discussing limitations, advantages, future perspectives, and challenges of both MXenes and MXene-based materials. The text covers up-to-date research in the field with a strong focus on novel findings in various devices along with core technological advancements that have been made in recent years. MXenes discusses sample topics such as: Properties of MXenes, including strong hydrophilicity, exceptional conductivity, high elastic mechanical strength, large surface-to-volume ratio, and chemical stability Applications of MXenes in energy storage, optoelectronics, spintronics, biomedicine, electro-catalysis, photocatalysis, membrane separation, supercapacitors, and batteries Performance factors that can hinder the efficacy of MXenes, including aggregation, difficulty obtaining a single layer, restacking, and oxidation of MXene nanosheets State-of-the-art progress in the field of gas sensors and electrochemical biosensors for the detection of various biomolecules, pharmaceutical drugs, and environmental pollutants Containing everything readers need to know about this exciting new class of 2D materials, MXenes is an essential reference for professionals working in advanced materials science, flexible electronics, nanoelectronics, and the energy industry, along with chemists, material scientists, and engineers in nanoscience and nanotechnology.

Author: Babak Anasori
Publisher: Springer Nature
ISBN: 3030190269
Category : Technology & Engineering
Languages : en
Pages : 534

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Book Description
This book describes the rapidly expanding field of two-dimensional (2D) transition metal carbides and nitrides (MXenes). It covers fundamental knowledge on synthesis, structure, and properties of these new materials, and a description of their processing, scale-up and emerging applications. The ways in which the quickly expanding family of MXenes can outperform other novel nanomaterials in a variety of applications, spanning from energy storage and conversion to electronics; from water science to transportation; and in defense and medical applications, are discussed in detail.

Author: Yury Gogotsi
Publisher: CRC Press
ISBN: 1498703070
Category : Science
Languages : en
Pages : 712

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Book Description
This title features 11 new chapters unique to this edition, including chapters on grain boundaries in graphene, 2D metal carbides and carbonitrides, mechanics of carbon nanotubes and nanomaterials, biomedical applications, oxidation and purification of carbon nanostructures, sintering of nanoceramics, hydrothermal processing, nanofibers, and nanomaterials safety. It offers a comprehensive approach with a focus on inorganic and carbon-based nanomaterials, including fundamentals, applications, synthesis, and characterization. This book also provides a unique angle from the nanomaterial point of view on application, synthesis, and characterization not found in any other nanomaterials book on the market.

Author: Kalim Deshmukh
Publisher: John Wiley & Sons
ISBN: 1119901049
Category : Technology & Engineering
Languages : en
Pages : 580

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Book Description
MXene Reinforced Polymer Composites This volume is the first book to comprehensively explore the various fabrication and processing strategies for MXene-reinforced polymer composites including detailed characterizations and their numerous applications. The book systematically provides a critical discussion on the synthesis and processing methods, structure, properties, characterizations, surface chemistry, and functionalization strategies of MXenes and their utilization as efficient nanofiller into various polymer matrices to form high-performance polymer composites. The book provides a deep insight into the recent state-of-the-art progress in MXene-reinforced polymer composites, discussing several critical issues and providing suggestions for future work. The key features of this book are: Providing fundamental information and a clear understanding of the synthesis, processing, compositions, structure, and physicochemical properties of MXenes; Presenting a comprehensive review of several recent accomplishments and key scientific and technological challenges in developing MXene-reinforced polymer composites; Exploring various processing and fabrication methods of MXene-reinforced polymer composites; Providing deep insight into fundamental properties and various emerging applications of MXene-reinforced polymer/composites. Audience Researchers, postgraduates, and industry engineers working in materials science, polymer science, materials engineering, and nanotechnology, as well as technologists in electronic, electrical, and biomedical industries.

Author: Chuanfang Zhang
Publisher: John Wiley & Sons
ISBN: 111986951X
Category : Technology & Engineering
Languages : en
Pages : 788

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Book Description
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.

Author: Kishor Kumar Sadasivuni
Publisher: Elsevier
ISBN: 0128225866
Category : Technology & Engineering
Languages : en
Pages : 796

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Book Description
MXenes and their Composites: Synthesis, Properties and Potential Applications presents a state of the art overview of the recent developments on the synthesis, functionalization, properties and emerging applications of two-dimensional (2D) MXenes and their composites.The book systematically describes the state-of-the-art knowledge and fundamentals of MXene synthesis, structure, surface chemistry and functionalization. The book also discusses the unique electronic, optical, mechanical and topological properties of MXenes. Besides, this book covers the various emerging applications of MXenes and their composites across different fields such as energy storage and conversion, gas sensing and biosensing, rechargeable lithium and sodium-ion batteries, lithium-sulphur and multivalent batteries, electromagnetic interference shielding, hybrid capacitors and supercapacitors, hydrogen storage, catalysis and photoelectrocatalysis, gas separation and water desalination, environmental remediation and medical and biomedical applications. All these applications have been efficiently discussed in the specific chapters and in each case, the processing of MXene composites has also been discussed.This book will be an excellent reference for scientists and engineers across various disciplines and industries working in the field of highly promising 2D MXenes and their composites. The book will also act as a guide for academic researchers, material scientists, and advanced students in investigating the new applications of 2D MXenes based materials. - Covers fundamentals of technologically important MAX phases, MXene derivatives, MXene synthesis methods, intercalation and delamination strategies, surface functionalization, fundamental characteristics and properties - Demonstrates major application areas of MXenes, including catalytic, energy storage and energy generation, flexible electronics, EMI shielding, sensors and biosensors, medical and biomedical, gas separation and water desalination - Presents a detailed discussion on the processing and performance of various MXenes towards different applications

Author: Zhuohao Xiao
Publisher: Springer Nature
ISBN: 3030593738
Category : Technology & Engineering
Languages : en
Pages : 404

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Book Description
In this book, the authors cover the recent progress in the synthesis, characterization and application of various multi-layered carbides, carbonitrides and nitrides. Moreover, the processing and development of MXene-based composites are elaborated, focusing on their applications and performances as transparent conductors in environmental remediation and energy storage systems.