Growth Kinetics And Properties Control Of Two Dimensional Nanostructures At The Liquid Interface

Since its emergence in the 1980s, nanoscience and nanotechnology research areas are rapidly expanding. It contributes to a broad range of fields from chemistry, physics, biology, and materials science to various engineering. Nowadays, nanomaterials have already come into almost every field of our lives, such as electronics, energy converting and storage, and biomedicines. Especially, after graphene was discovered in 2004, two-dimensional (2D) materials attracted an increased interest. There is a boost in the research on controlling nanostructures and manipulating their properties. The bottom-up approach using individual atoms and molecules as building blocks to construct nanoscale materials and structures offers an opportunity to create new 2D structures or phases that don't exist in the bulk. A generic synthetic method with structure control and property engineering is highly desired for exploring 2D materials' unique properties. The air-water interface is an ideal 2D environment for the controllable synthesis of 2D materials. By employing a monolayer of self-assembled ionized amphiphilic molecules as a soft template at the air-water interface, 2D nanocrystals form in the electrical double-layer confined region and grow epitaxially directed by soft template packings. Therefore, this synthesis technique was named the ionic layer epitaxy (ILE). This dissertation focuses on the study of this 2D materials synthesis system at the air-water interface, including the growth kinetics and mechanism investigations, facet and thickness control, element and defect manipulation, and the advanced application of these 2D materials in electrochemical, physical and biological fields.

This book introduces the latest methods for the controlled growth of nanomaterial systems. The coverage includes simple and complex nanomaterial systems, ordered nanostructures and complex nanostructure arrays, and the essential conditions for the controlled growth of nanostructures with different morphologies, sizes, compositions, and microstructures. The book also discusses the dynamics of controlled growth and thermodynamic characteristics of two-dimensional nanorestricted systems. The authors introduce various novel synthesis methods for nanomaterials and nanostructures, such as hierarchical growth, heterostructures growth, doping growth and some developing template synthesis methods. In addition to discussing applications, the book reviews developing trends in nanomaterials and nanostructures.

2.6.2 Electrodes for Electrochemistry

2D NANOMATERIALS The book provides a comprehensive overview of the synthesis, modification, characterization, and application of 2D nanomaterials. In recent years, 2D nanomaterials have emerged as a remarkable cornerstone in the field of advanced materials research, with their unique properties and versatile applications captivating the attention of scientists and engineers worldwide. This book is a testament to the ever-growing interest and importance of 2D nanomaterials in the realm of materials science, nanotechnology, pharmaceuticals, and a myriad of engineering specializations. The book is structured into three sections, each delving into different aspects of 2D nanomaterials. The first section explores the synthesis of these materials, providing an overview of both top-down and bottom-up strategies. Understanding the methods by which these materials can be synthesized is crucial for advancing their potential applications. Additionally, this section details the structural characterization of 2D nanomaterials, shedding light on their intricate compositions and properties. The second section examines the diverse characteristics exhibited by 2D nanomaterials. From their magnetic and mechanical properties to their electrical, plasmonic, and optical behaviors, these materials possess an array of intriguing attributes that make them highly attractive for a wide range of applications. This section of the book provides a comprehensive understanding of these properties, enabling readers to appreciate the unique potential of 2D nanomaterials. The final section focuses on the applications of 2D nanomaterials, highlighting their use in various fields such as energy, water purification, biomedical applications, multimodal tumor therapy, and supercapacitor technology.

After the 2010 Nobel Prize in Physics was awarded to Andre Geim and Konstantin Novoselov "for groundbreaking experiments regarding the two-dimensional material graphene," even more research and development efforts have been focused on two-dimensional nanostructures. Illustrating the importance of this area in future applications, Two-Dimensional Nanostructures covers the fabrication methods and properties of these materials. The authors begin with discussions on the properties, size effect, applications, classification groups, and growth of nanostructures. They then describe various characterization and fabrication methods, such as spectrometry, low-energy electron diffraction, physical and chemical vapor deposition, and molecular beam epitaxy. The remainder of the text focuses on mechanical, chemical, and physical properties and fabrication methods, including a new mechanical method for fabricating graphene layers and a model for relating the features and structures of nanostructured thin films. With companies already demonstrating the capabilities of graphene in a flexible touch-screen and a 150 GHz transistor, nanostructures are on their way to replacing silicon as the materials of choice in electronics and other areas. This book aids you in understanding the current chemical, mechanical, and physical processes for producing these "miracle materials."

Generation of Polymers and Nanomaterials at Liquid-Liquid Interfaces: Application to Crystalline, Light Emitting, and Energy Materials, Second Edition is an innovative guide to the synthesis and processing of materials through liquid-liquid interfaces. This second edition has been revised and expanded, with a new chapter on light emitting materials and increased emphasis towards applications. The book aims to highlight the versatility of the interface between two liquids, providing a unique environment for synthesizing materials with highly tuned, desirable properties. In this revised and expanded second edition, the advanced applications of the synthesized materials and the two-phase systems are highlighted, with real potential within flexible electronics, energy storage, enhanced oil recovery, and sensors. This is supported by detailed coverage of interfacial processes and the fundamental physical chemistry behind them. The first two chapters provide an overview of interfaces in natural and biological systems, and outline the fundamental properties of the interface. Chapters 3 and 4 are devoted to the synthesis and self-organization of nanoparticles and polymers through interfacial systems. The synthesis of conductive, fluorescent and conventional polymers and their properties are extensively covered. Chapters 5 and 6 focus on novel applications. This book is of interest to researchers, scientists, and advanced students, in polymer synthesis, polymer chemistry, polymer science, nanomaterials and nanotechnology, polymer composites, materials science, energy, flexible electronics, and chemical engineering. In industry, this supports scientists, R&D, and other professionals, working with polymeric materials for applications in energy, electronics, sensors, and oil & gas. Provides new ideas for the design of fluorescent polymers, conductive polymers, nanoparticle arrays, thin films, and novel 2D materials Includes detailed coverage of synthesis and processing of polymers and nanomaterials at liquid-liquid interfaces Explores state-of-the-art applications across flexible electronics, energy storage, enhanced oil recovery, and sensors

And, on the same time scale there is a concomitant decrease in the SAXS form factor from disordered nanoparticles. X-ray beam transmission at different vertical heights characterizes the heptane and DEG bulk and interfacial regions, while monitoring the time dependence of SAXS at and near the DEG/heptane interface gives a clear picture of the evolution of nanoparticle assembly at this liquid/liquid interface. These SAXS observations of self-limited nanoparticle monolayer formation at the DEG/heptane interface are consistent with those using the less direct method of real-time optical reflection monitoring of that interface.

Carbon nanotubes (CNTs) have unique transport and elastic properties due to their high aspect ratios. Hence there is considerable interest in using these tubes as field emitter cathodes, composite materials with enhanced electrical and mechanical properties, electronic components and recently for hydrogen storage applications taking advantage of the high specific surface areas. In this thesis three different aspects of carbon nanotubes were studied: (1) Controlled growth of single walled nanotubes (SWNTs), (2) Electric field directed Chemical Vapor Deposition (CVD) of multi walled (MWNTs) and (3) "Spillover" Mechanism of hydrogen storage in Pt-SWNT composites. The kinetics of carbon nanotube growth was studied in the context of the CVD process. A generic model for growth of 1-d nano structures via the Vapor-Liquid-Solid (VLS) mechanism is applied to the nanotube growth. This model considers the energetics of individual mass transfer steps through each phase and at the phase interfaces. The flux is then written in terms of the change in chemical potential. Laser interferometry was applied in a cold-wall thermal CVD reactor to measure the growth of the MWNT films in-situ. Temperature dependent studies in the steady-state regime were used to obtain activation energies which are consistent with the interfacial transport step. Consideration of the catalyst activation/de-activation process in the non-steady regimes requires the rate limiting step to be in the vapor-liquid transition. Application of an electric field during the MWNT growth was found to enhance both the growth rate and alignment of the MWNTs. Temperature dependent studies in the presence and absence of the electric field show that there are actually two activated processes involved, with rate-limiting step being independent of applied field at high temperature. At higher temperatures, the rate-limiting step is the carbon dissolution into the catalyst particle, while at lower temperatures it is the carbon dissociation at the catalyst-vapor interface that limits the growth. Application of an electric field enhances the decomposition of the C precursor in the vapor phase, thus circumventing this low temperature activation barrier. The enhanced alignment of the MWNTs with the electric field is explained by tensile stretching overcoming the defect-induced kinking of the MWNTs. Calculations show that this benefit is obtained at a minimum field level, with no benefit arising from further increase in field strength. The catalyst particle size is one of the key parameters that determine the morphology of the 1D carbon nanostructures in both processes studied. The thermodynamics of the nano-particle formation and carbon dissolution are studied and applied to these processes. While the diameter serves to template the CNT diameter, the Gibb's Thompson effect predicts a size dependent suppression of melting point which determines the nature of CNT formed. In the CVD process, higher pressures were found to form larger particle sizes which led to nanofiber growth. At these diameters, the melting point suppression puts the Fe-C particle in a dual solid-liquid phase. Carbon flux accumulates in the dual phase during growth until the dual phase becomes energetically unfavorable. At this point, the particle reverts to a single solid phase regime by discarding excess carbon, resulting in a discontinuous graphitic structure characteristic of Carbon nanofibers. For smaller particles, the phase is entirely liquid and leads to steady state carbon flux and CNT growth. Controlling the iron bearing precursor concentration of the solution fed into the floating catalyst reactor was found to control particle size, and hence SWNT diameter, within this regime. For similar catalyst particle size distributions, increasing the temperature increased the range of SWNT diameters and chiralities obtained. The thermodynamic energy barrier for SWNT formation at the different diameters was calculated and shown to be consistent with the observed variation. Finally, the mechanism of hydrogen uptake in transition metal-doped SWNT was studied. Molecular hydrogen, dissociated by metal catalyst nanoparticles, diffuses to the nanotube surface forming stronger bonds. In-situ 4-probe conductivity tests were performed on mats of Pt doped SWNT during hydrogen uptake. On hydrogen charging the resistivity of the Pt doped SWNT mat increased. This is due to the formation of C-H bonds, which breaks the symmetry of the CNT electronic structure resulting in formation of localized defects, thereby increasing the resistivity. Initial studies of the temporal dependence of hydrogen uptake suggest a diffusion-limited process. XPS was employed to measure the extent of sp3 C-H bonding.

Nanomaterials for Hydrogen Storage Applications introduces nanomaterials and nanocomposites manufacturing and design for hydrogen storage applications. The book covers the manufacturing, design, characterization techniques and hydrogen storage applications of a range of nanomaterials. It outlines fundamental characterization techniques for nanocomposites to establish their suitability for hydrogen storage applications. Offering a sound knowledge of hydrogen storage application of nanocomposites, this book is an important resource for both materials scientists and engineers who are seeking to understand how nanomaterials can be used to create more efficient energy storage solutions. Assesses the characterization, design, manufacture and application of different types of nanomaterials for hydrogen storage Outlines the major challenges of using nanomaterials in hydrogen storage Discusses how the use of nanotechnology is helping engineers create more effective hydrogen storage systems

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.