Download or read book Structure and Applications of Gold in Nanoporous Form written by Jay K. Bhattarai and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanoporous gold (np-Au) has many interesting and useful properties that make it a material of interest for use in many technological applications. Its biocompatible nature and ability to serve as a support for self-assembled monolayers of alkanethiols and their derivative make it a suitable support for the immobilization of carbohydrates, enzymes, proteins, and DNA. Its chemically inert, physically robust and conductive high-surface area makes it useful for the design of electrochemistry-based chemical/bio-sensors and reactors. Furthermore, it is also used as solid support for organic molecular synthesis and biomolecules separation. Its enhanced optical property has application in design of plasmonics-based sensitive biosensors. In fact, np-Au is one of the few materials that can be used as a transducer for both optical and electrochemical biosensing. Due to the presence of low-coordination surface sites, np-Au shows remarkable catalytic activity for oxidation of molecules like carbon monoxide and methanol. Owing to the importance of np-Au, in this chapter we will highlight different strategies of fabrication of np-Au and its emerging applications based on its unique properties.
Download or read book Nanoporous Gold written by Arne Wittstock and published by Royal Society of Chemistry. This book was released on 2012-03-28 with total page 265 pages. Available in PDF, EPUB and Kindle. Book excerpt: High-surface-area materials have recently attracted significant interest due to potential applications in various fields such as electrochemistry and catalysis, gas-phase catalysis, optics, sensors and actuators, energy harvesting and storage. In contrast to classical materials the properties of high-surface-area materials are no longer determined by their bulk, but by their nanoscale architecture. Nanoporous gold (np-Au) represents the fascinating class of mesoporous metals that have been intensively investigated in recent years. The current interest and the increasing number of scientific publications show that np-Au by itself is an outstanding nano-material that justifies a book devoted to all aspects of its properties and applications. The resulting publication is a discussion of this unique nano-material and is an accessible and comprehensive introduction to the field. The book provides a broad, multi-disciplinary platform to learn more about the properties of nanoporous gold from an inter-disciplinary perspective. It starts with an introduction and overview of state-of-the-art applications and techniques characterizing this material and its applications. It then covers the progress in research within the last years. The chapters are in-depth overviews written by the world's leading scientists in the particular field. Each chapter covers one technique or application so that the reader can easily target their favoured topic and will get the latest and state-of-the-art information in the field.
Download or read book Noble and Precious Metals written by Mohindar Seehra and published by BoD – Books on Demand. This book was released on 2018-07-04 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of copper, silver, gold and platinum in jewelry as a measure of wealth is well known. This book contains 19 chapters written by international authors on other uses and applications of noble and precious metals (copper, silver, gold, platinum, palladium, iridium, osmium, rhodium, ruthenium, and rhenium). The topics covered include surface-enhanced Raman scattering, quantum dots, synthesis and properties of nanostructures, and its applications in the diverse fields such as high-tech engineering, nanotechnology, catalysis, and biomedical applications. The basis for these applications is their high-free electron concentrations combined with high-temperature stability and corrosion resistance and methods developed for synthesizing nanostructures. Recent developments in all these areas with up-to-date references are emphasized.
Download or read book Nanoporous Gold Characterization Structural Modification and Use as a Solid Support for Biomolecule Immobilization written by Abeera Sharma and published by . This book was released on 2014 with total page 167 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanoporous gold (NPG) has immense technological applications owing to a plethora of properties like large surface area to volume ratio, plasmonic properties, stable gold-thiolate bond formation and a wide range of pore sizes. The surface morphology of nanoporous gold has been altered previously by dealloying and thermal annealing to increase/decrease the pore size and change the surface area. We provide a novel electrochemical annealing technique for post dealloying modification wherein electrochemical sweep cycles in different electrolytes at positive potentials leads to a subsequent increase in pore sizes of nanoporous gold as studied using scanning electron microscopy. Tailoring the surface of nanoporous gold allows us to characterize and study self-assembled monolayers of alkanethiols, including those terminated by carbohydrate moieties. The orientation of these thiols on nanoporous gold is not uniform due to the interconnected framework of pores and ligaments and we try to offer a fair comparison between flat gold and nanoporous gold to determine the surface coverage of these self-assembled monolayers. Carbohydrate-lectin interactions have been studied with the help of dendrimers as linkers. Dendrimers (polyamidoamine generation 4 and 5) have been used as linkers due to their multivalent interactions with carbohydrate moieties and impedance spectroscopy as well as atomic force microscopy techniques have been utilized to study dendrimers attached on nanoporous gold surface using covalent immobilization. This study aims at providing a comprehensive surface property analysis of nanoporous gold.
Download or read book Linking the Structure and Mechanical Behavior of Nanoporous Gold written by Ye Sun and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis of Nanoporous Gold Structures Via Dealloying of Electrodeposited Au Ni Alloys written by Eric Rouya and published by . This book was released on 2007 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Applications of Nanoporous Gold for the Immobilization of Biomolecules written by Kenise Jefferson and published by . This book was released on 2010 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Catalytic Application of Nano Gold Catalysts written by Neeraj Kumar Mishra and published by BoD – Books on Demand. This book was released on 2016-08-31 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gold, considered catalytically inactive for a long time, is now a fascinating partner of modern chemistry, as scientists such as Bond, Teles, Haruta, Hutchings, Ito and Hayashi opened new perspectives for the whole synthetic chemist community. Recently gold has attracted significant attention due to its advantageous characteristics as a catalytic material and since it allows easy functionalization with biologically active molecules. In this context, when gold is prepared as very small particles, it turns out to be a highly active catalyst. However, such a phenomenon completely disappears when the gold particle size grows into the micrometer range. Therefore, the preparation for obtaining an active gold catalyst is so important. The primary objective of this book is to provide a comprehensive overview of gold metal nanoparticles and their application as promising catalysts.
Download or read book The Mechanism and Applications of Nanoporous Gold Derived from Dealloying Au based Metallic Glass written by 徐奕 and published by . This book was released on 2018 with total page 135 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modification and Utilization of Nanoporous Gold for Loading and Release of Drugs written by Ibtisam Mohammed Al-badri and published by . This book was released on 2016 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanoporous gold (np-Au) is a sponge-like structure of gold, which can be created by removing the less noble element from the precursor alloy, most typically silver or copper, using different chemical or electrochemical methods. It consists of interconnected ligaments and gaps between the ligaments, whose width can range from a few nanometers to a few hundreds of nanometers, creating a high surface area-to-volume ratio. Due to its many important properties (e.g., conductivity, high surface area-to-volume ratio, plasmonic response, biocompatibility, chemically inertness, and physically robustness), np-Au is suitable for different types of applications, including as a transducer for biosensors, in catalysis, for biomolecule separation, as a substrate for enzyme immobilization, and in drug delivery. The widths of the ligaments and gaps of np-Au can be easily tuned by varying conditions during the pre- or post-production process, for example, time kept in an acid bath and post-annealing (e.g. thermal, chemical, and electrochemical), depending on the requirement of the study. Thermal annealing is a commonly used process for tuning the ligaments and pore size of np-Au. However, the effects of thermal annealing on modification of ligaments and gaps sizes are not completely understood and more research needs to be done. Herein, we have explored the effect of annealing time and thickness of the np-Au sample on modification of ligaments and gaps. Furthermore, we used the electroless plating method to cover the pores or gaps partially on the surface without modifying the interior of np-Au. As-prepared np-Au was then studied as a platform for molecular loading and releasing kinetics for the possible use in drug delivery. We have found that simply applying the electroless deposition for 2 to 5 min can drastically decrease the rate of release of the molecules, and flow cell-based loading is the preferred way to load the molecules inside np-Au compared to the static method. The structure of the np-Au monoliths before and after the modification was characterized using Energy-Dispersive X-ray Spectroscopy (EDS) and scanning electron microscopy (SEM), whereas the molecular loading and releasing studies were performed using UV-Vis spectrophotometer.
Download or read book Theoretical Insights Into Catalysis on Nanoporous Gold from Ab Initio Molecular Dynamics written by Yong Li and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanoporous gold (np-Au) has recently emerged as a highly selective catalyst, potentially suited to environmentally friendly and low-temperature applications. In contrast to the more extensively studied gold nanoparticle catalysts, the mechanistic understanding of catalytic processes on pristine and oxide-coated np-Au is far less developed. Quantum chemical methods, in particular, those based on density functional theory (DFT) can be used successfully to achieve a mechanistic understanding at the microscopic level, which is needed to optimize materials based on np-Au with respect to their catalytic properties. In this thesis, I summarize my computational work devoted to a deeper insight into the chemistry and physics of np-Au as a catalyst. Modern surface science has revealed that a catalyst is not a rigid body but undergoes rapid (sometimes irreversible) dynamic changes during chemical processes occurring on its surface. Whereas many theoretical studies still use an oversimplified model of a metal catalyst as a rigid, clean, and perfect surface, my PhD work examines dynamic processes occurring on the surface of np-Au in response to changes of the chemical environment, such as oxygen-induced surface restructuring, the formation of surface oxygen chain structures, and elementary catalytic reactions on np-Au, by using ab initio molecular dynamics (AIMD) simulations. In addition to AIMD simulations, traditional “static” DFT computations have been performed to verify minima and transition states in the reaction energy landscape and to construct reaction energy diagrams. The main results of the publications comprising the foundation of this thesis can be summarized as follows. Although np-Au consists of almost pure gold, silver atoms are also present on the surface as residues of the preparation process. Therefore, its surface chemistry turns out to be more complex than anticipated. Interactions between Au atoms and O atoms pre-adsorbed and/or generated during catalysis and the involvement of Ag impurities result in complex surface dynamics. First of all, with regard to pristine np-Au, the theoretical studies reveal that surface O atoms dynamically form one- and two-dimensional -(Au-O)- chains on a stepped Au(321) surface and lead to surface restructuring. In contrast, no chain formation has been found on Au(111), pointing to higher structural flexibility and propensity for restructuring of the stepped surface. Furthermore, our study predicts migration of subsurface Ag atoms to the surface, i.e. adsorbate-induced Ag surface segregation, in the presence of adsorbed atomic oxygen. Second, my thesis addresses the physics and chemistry of np-Au material functionalized with cerium oxide. To probe the reactivity of these systems and the involvement of inherent particle-support interactions towards CO oxidation, AIMD simulations and static DFT computations were carried out. As models, Ce10O20/19 NPs supported on thermodynamically stable Au(111) and on the stepped (rough) Au(321) surface were employed. For the ceria/Au(111) system, the simulations revealed the preference of a Mars-van-Krevelen type of reaction mechanism, in which a CO molecule first reacts with a lattice O atom of ceria rather than with an activated O22- surface species, forming CO2 and leaving an O vacancy behind. This vacancy becomes subsequently refilled by an O atom which diffuses from the site of the reaction of O2 with another CO molecule (at the gold-ceria perimeter). My studies also revealed that, in contrast, CO adsorption on the stepped Au(321) surface (in proximity to the ceria nanoparticle) may lead to the dynamic extraction of Au atoms from the surface resulting in Au-CO carbonyl species, which may subsequently diffuse on the Au surface and react with lattice O of ceria to CO2 with very low activation energy. After the reaction step, the extracted bare Au atom attaches to a step on the Au surface. As this is not the original site, this part of the catalytic cycle leads to a rearrangement of the surface structure. The second part of the cycle is likely to be the same as found for the ceria/Au(111) system. Finally, this thesis discusses the correlation between two types of catalysts that are “inverse” with respect to each other, namely, Au nanoparticles deposited on ceria and ceria nanoparticles deposited on Au (being the focus of this thesis), with respect to all aspects relevant for the surface reactivity, such as surface dynamics, charge transfer between the gold and the oxide phases, and the mechanism of CO oxidation.
Download or read book Nanoporous Gold written by Arne Wittstock and published by Royal Society of Chemistry. This book was released on 2012 with total page 265 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book provides a broad, multidisciplinary platform to learn more about the properties of nanoporous gold from an interdisciplinary perspective from an overview of state-of-the-art applications and techniques to the latest research progress.
Download or read book New Way of Synthesis of Uniform Gold Nanoparticles for the Detection of Few Molecules written by Rana Omar and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Controlled synthesis of metallic nanoparticles (MNPs), according to particular morphologies and dimensions, is an interdisciplinary field of research because of the new, varied, rich and complex physical properties of MNPs. These properties are mainly governed by the collective oscillations of conduction electrons called plasmons. This phenomenon is optically reflected by the sensitivity of the MNPs to the change in the surrounding refractive index and by the shift of their plasmon resonance band. This feature, according to the morphology of MNPs, is used in fairly modern applications such as cancer phototherapy and the development of the ultrasensitive sensors based on Surface Plasmon Resonance (SPR) or Surface Enhanced Raman Spectroscopy (SERS). The sensitivity of MNPs as sensors is not only directly related to the chemical and crystalline nature of the metal but also to their ability to adsorb target molecules, absorb and/or confine and enhance incident light. This last property is generally more remarkable as the distance separating the MNPs is small. Thus, the control of the size, shape and density of the MNPs is of major interest. Therefore, the development of new synthesis methods of MNPs is still relevant. Moreover, the fabrication of uniform metallic nanoparticles is mainly achieved by colloidal synthesis particularly by "seed mediated growth". On the other hand, this method always has certain limitations in the preparation time and the control of the size and shape. In this context, we have, in this thesis, developed a new fabrication method of MNPs of different shapes. The idea is to structure a polymer (PMMA) in the form of a nanoporous film and to use the nanopores as synthesis reactor for MNPs. Thus, the objective of this thesis was to investigate the proposed synthesis method in order to develop new detection nanosensors based on SERS phenomenon. The work in this thesis has been divided into three main parts: the first is to study the synthesis mechanism in order to optimize the formation process of uniform metallic structures. The second aims to change the shape of the MNPs by playing on the parameters of synthesis. In parallel with these two aspects, an important task was devoted to morphological analysis using structural analysis techniques, and to the determination and the modelling of the optical responses of these MNPs particularly by the technique of spectroscopic ellipsometry.
Download or read book Handbook on Synthesis Strategies for Advanced Materials written by A. K. Tyagi and published by Springer Nature. This book was released on 2022-01-04 with total page 856 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents state-of-the-art coverage of synthesis of advanced functional materials. Unconventional synthetic routes play an important role in the synthesis of advanced materials as many new materials are metastable and cannot be synthesized by conventional methods. This book presents various synthesis methods such as conventional solid-state method, combustion method, a range of soft chemical methods, template synthesis, molecular precursor method, microwave synthesis, sono-chemical method and high-pressure synthesis. It provides a comprehensive overview of synthesis methods and covers a variety of materials, including ceramics, films, glass, carbon-based, and metallic materials. Many techniques for processing and surface functionalization are also discussed. Several engineering aspects of materials synthesis are also included. The contents of this book are useful for researchers and professionals working in the areas of materials and chemistry.
Download or read book Gold Nanoparticles For Physics Chemistry And Biology Second Edition written by Catherine Louis and published by World Scientific. This book was released on 2017-06-02 with total page 681 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gold Nanoparticles for Physics, Chemistry and Biology offers an overview of recent research into gold nanoparticles, covering their discovery, usage and contemporary practical applications.This Second Edition begins with a history of over 2000 years of the use of gold nanoparticles, with a review of the specific properties which make gold unique. Updated chapters include gold nanoparticle preparation methods, their plasmon resonance and thermo-optical properties, their catalytic properties and their future technological applications. New chapters have been included, and reveal the growing impact of plasmonics in research, with an introduction to quantum plasmonics, plasmon assisted catalysis and electro-photon conversion. The growing field of nanoparticles for health is also addressed with a study of gold nanoparticles as radiosensibiliser for radiotherapy, and of gold nanoparticle functionalisation. This new edition also considers the relevance of bimetallic nanoparticles for specific applications.World-class scientists provide the most up-to-date findings for an introduction to gold nanoparticles within the related areas of chemistry, biology, material science, optics and physics. It is perfectly suited to advanced level students and researchers looking to enhance their knowledge in the study of gold nanoparticles.
Download or read book Microfabrication and Characterization of Nanoporous Gold Structures written by Erkin Şeker and published by . This book was released on 2007 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation reports on the underlying mechanisms of stress and morphology evolution during and after dealloying with respect to annealing temperatures for structures with various geometric constraints. Understanding the fundamental mechanisms that lead to morphology and stress-state evolution via dealloying and thermal treatment will be valuable in developing applications incorporating np-Au in sensors and actuators. In addition, an interesting wetting equilibrium observed during the fabrication experiments will be described. This phenomenon was later utilized for the development of a composite np-Au and silicon elastomer. The synthesis and applications of this material will be outlined. Finally, implications for future studies and applications will be discussed.
Download or read book Gold Chemistry written by Fabian Mohr and published by John Wiley & Sons. This book was released on 2009-04-20 with total page 425 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by world-class authors, this most recent major book on the topic highlights new and current trends as well as future directions. It is comprehensive in its scope, covering all aspects of gold chemistry -- from homogeneous to heterogeneous catalysis, from supramolecular assemblies to sensors and medicinal applications. The result is an invaluable work for both organic and inorganic chemists working in universities and industry, as well as material scientists.
