Author: Ryan Evan Schwarb Publisher: ISBN: Category : Fuel Languages : en Pages : 80
Book Description
Recent advances in the science of nanoparticle synthesis have resulted in new core-shell nanoparticles displaying novel, unique, and potentially valuable properties for their use in propellants, fuels, and explosives. This research was conducted in support of the Propulsion Directorate of the Air Force Research Laboratory aimed at the development of functional reactive nanoparticles as fuel additives for improved thermal stability. In this work, oxidation of highly reactive zero-valent iron nanoparticles coated to prevent agglomeration and early reaction was studied as a novel approach to remove oxygen from the fuels. The particles were synthesized using sonochemistry, a well-established technique to self assemble core-shell nanoparticles, where the solution of pentacarbonyl Fe(CO)5 in dodecane was sonciated in the presence of an encapsulating compound, or shell material, to produce core-shell nanoparticles (CSNPs). The nanoparticles were stable at the temperatures below 120°C; at elevated temperatures, the shell material allows oxygen to permeate and react with the iron core depleting the oxygen from solution. It was observed that altering the structure of the shell material significantly influences the temperature-controlled oxidation of CSNPs over a range from 130°C to 188°C. This thesis investigates various shell material parameters including chain length, structural perturbation, and functional group to protect the iron core from oxidation at low temperatures and enable temperature-controlled oxidation of the iron core at higher temperatures. The impact of shell material parameters on CSNP solubility, particle diameter and temperature-controlled oxidation are investigated and reported.
Author: He Li Publisher: ISBN: 9780549490159 Category : Nanostructured materials Languages : en Pages : 138
Book Description
Fe, Co, FexCo(1-x) and AuxFe (1-x) alloy nanoparticles encapsulated by graphitic carbon are synthesized by chemical vapor deposition. Transmission electron microscopy (TEM) reveals that the nanoparticles are mostly about 10 nm in diameter and each nanoparticle is enclosed by at least one layer of graphitic carbon. Phase identification by high resolution TEM indicates the metallic phases were indeed obtained and preserved, even after three years of exposure to ambient conditions. The Fe-containing nanoparticles were found to be either BCC or FCC or Fe 3C, the Co nanoparticles being FCC, the FexCo(1-x) (0.1
Author: Kamel A. Abd-Elsalam Publisher: Elsevier ISBN: 0128245093 Category : Technology & Engineering Languages : en Pages : 798
Book Description
Green Synthesis of Silver Nanomaterials illustrates how to biologically scale up silver nanoparticle synthesis. This book covers green synthesis of silver nanomaterials, via plants, agricultural waste, fungi, and microorganisms. Sections cover the synthesis and characterization of chemical and green synthesis, various types of silver nanomaterialism, the ability of different fungal species, such as filamentous fungi, to produce silver nanoparticles, the microbial synthesis of silver NMs, biosynthesis mechanisms, toxicity, fate and commercialization. As examples, greener pathways and mechanisms, toxicity of silver nanoparticles in aquatic life and in natural eco-systems, and strategies for the scaling up of green-synthesized nanomaterials are discussed. With the extended work in enhancing nanomaterials synthesis performance, and discovering their biomedical, environmental, and agricultural applications, it is hoped that the execution of these methods on a large scale and their industrial applications in different fields will take place in the near future. - Assesses the impact of a large variety of silver-based nanostructures in the biomedical, environmental and agri-food sectors - Discusses the major synthesis methods used for effectively processing plant-based silver nanoparticles - Outlines the potential and major challenges for adopting green synthesis methods on a mass scale
Author: Publisher: ISBN: Category : Languages : en Pages : 6
Book Description
Core-shell nanostructures have attracted much attention due to their unique and tunable properties relative to bulk structures of the same materials, making core-shell nanoparticles candidates for a variety of applications with multiple functionalities.[1,2] Intriguing magnetic behavior can be tailored by variation of size, interface, crystal orientation, and composition, and core-shell nanostructures with noble-metal shells yield novel optical responses[3] and enhanced electrocatalytic activity.[4].
Author: Abdelhamid Elaissari Publisher: CRC Press ISBN: 9780203911488 Category : Science Languages : en Pages : 480
Book Description
Amidst developments in nanotechnology and successes in catalytic emulsion polymerization of olefins, polymerization in dispersed media is arousing an increasing interest from both practical and fundamental points of view. This text describes ultramodern approaches to synthesis, preparation, characterization, and functionalization of latexes, nanopa
Author: Xin Tong Publisher: Springer Nature ISBN: 3030465969 Category : Science Languages : en Pages : 331
Book Description
This book outlines various synthetic approaches, tuneable physical properties, and device applications of core/shell quantum dots (QDs). Core/shell QDs have exhibited enhanced quantum yield (QY), suppressed photobleaching/blinking, and significantly improved photochemical/physical stability as compared to conventional bare QDs. The core-shell structure also promotes the easy tuning of QDs’ band structure, leading to their employment as attractive building blocks in various optoelectronic devices. The main objective of this book is to create a platform for knowledge sharing and dissemination of the latest advances in novel areas of core/shell QDs and relevant devices, and to provide a comprehensive introduction and directions for further research in this growing area of nanomaterials research.
Author: Publisher: ISBN: Category : Languages : en Pages :
Book Description
New fields of research in chemistry and physics require improved synthetic techniques for colloidal metal particles. This work reports two novel techniques for synthesising bimetallic core-shell nanoparticles. The first technique is the chemical deposition of transition metal salts onto gold nanoparticle seeds. The transition metals used were platinum, palladium and rhodium. Gold nanoparticle seeds were produced using published methods. The gold nanoparticles were stabilised with either citrate or thiol-based stabilisers and the effects of the different stabilisers were studied. The gold nanoparticle seeds and the bimetallic core-shell nanoparticles were characterised using UV-vis spectroscopy, HAADF imaging, AFM imaging and with cyclic voltammetry. The citrate-stabilised gold nanoparticle seeds provided a better starting material for the bimetallic core-shell nanoparticles, however this route had problems with aggregation and morphology. The thiol-stabilised gold nanoparticles had a better morphology, but the thiol-stabilisation meant that it was difficult to coat the gold nanoparticles. The second technique studied was the use of galvanic replacement technique for producing bimetallic core-shell nanoparticles, which provides a novel and rapid technique for coating gold nanoparticle seeds with platinum. The Au(core)-Pd(shell) bimetallic nanoparticle system stabilised with citrate was the most successful of the three bimetallic systems studied, producing core-shell particles of approximately 5 nm in diameter.
Author: Kyler James Carroll Publisher: ISBN: Category : Biosensors Languages : en Pages :
Book Description
The design of core/shell nanoparticles is of great interest for a wide range of applications. The primary focus of this dissertation is on the design and optimization of two synthetic routes. The first one is an aqueous reduction method using sodium borohydride and sodium citrate. This method was extended to design two types of core/shell nanoparticles, both of which have many applications in bio-sensing, magnetic resonance imaging, and magnetically guided SERS for the identification of environmental threats. The first, Fe/Ag core/shell nanoparticles were designed using a novel one-pot method by varying the AgNO3 addition time in the system. For example, if AgNO3 is added five minutes after the start of the reaction, the already formed Fe nanoparticles serve as seeds for heterogeneous nucleation and growth of Ag nanoparticles. The result of the synthesis was 50 nanometer spherical particles with a narrow size distribution. The second type, Fe/SiO2/Au core/shell nanoparticles were designed using a two-step method. First, 150 nanometer spherical Fe nanoparticles were synthesized followed by the addition of tetraethylorthosilicate (TEOS). This created a Fe/SiO2 core/shell nanoparticle to which HAuCl3 was added. In both cases, Fe/Ag and Fe/SiO2/Au, the formed nanoparticles were characterized and tested for the application as SERS active materials. The second part of this dissertation work was focused on using the polyol method to design bimetallic Cu/Ni, Fe/FeOx, and Co/C core/shell nanoparticles. In each case, the polyol method provided an easy one-pot reaction to synthesize these novel nanomaterials. The design of the Cu/Ni nanoparticles allowed for further insight into the polyol mechanism by independently investigating the factors that govern the formation of elemental Cu and Ni nanoparticles. By understanding the ability of the polyols to easily prepare metal and metal oxide nanoparticles, we were able to manipulate a one-pot reaction to design an aqueous ferrofluid consisting of Fe/FeOx nanoparticles. These spherical 15 nanometer particles were studied for their potential application as MRI contrast agents. In addition, the aqueous ferrofluid served as a precursor for the design of magnetic/luminescent core/shell nanoparticles. Finally, the polyol method was extended to create Co/C nanoparticles for permanent magnet applications.
Author: Jorge L. Chávez Benavides Publisher: ISBN: Category : Languages : en Pages :
Book Description
These studies suggested that the sequestered probes could interact with each other producing a dynamic quenching of the donor. Finally, we covalently attached another hydrophobic fluorescent probe to the particles to study the level of interaction with the solvent, observing that the probe preferred to react in the interior pores of the particles to reduce interaction with the polar media.
Author: Ryan Evan Schwarb
Author: He Li
Author: Kamel A. Abd-Elsalam
Author: 
Author: Abdelhamid Elaissari
Author: Xin Tong
Author: 趙劍雄
Author: 
Author: Kyler James Carroll
Author: Jorge L. Chávez Benavides