Download or read book ALD Functionalized Nanoporous Gold written by and published by . This book was released on 2011 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanoporous metals have many technologically promising applications but their tendency to coarsen limits their long-term stability and excludes high temperature applications. Here, we demonstrate that atomic layer deposition (ALD) can be used to stabilize and functionalize nanoporous metals. Specifically, we studied the effect of nanometer-thick alumina and titania ALD films on thermal stability, mechanical properties, and catalytic activity of nanoporous gold (np-Au). Our results demonstrate that even only one-nm-thick oxide films can stabilize the nanoscale morphology of np-Au up to 1000 C, while simultaneously making the material stronger and stiffer. The catalytic activity of np-Au can be drastically increased by TiO2 ALD coatings. Our results open the door to high temperature sensor, actuator, and catalysis applications and functionalized electrodes for energy storage and harvesting applications.
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 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 Fabrication and Surface Functionalization of Nanoporous Gold by Electrochemical Alloyin Dealloying of Au Zn in an Ionic Liquid and the Self Assembly of L Cysteine Monolayers written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nanoalloys written by Dominique Bazin and published by Elsevier Inc. Chapters. This book was released on 2013-03-12 with total page 101 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nanoalloys written by Florent Calvo and published by Elsevier. This book was released on 2020-06-26 with total page 526 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanoalloys, Second Edition, provides a self-contained reference on the physics and chemistry of nanoscale alloys, dealing with all important aspects that range from the theoretical concepts and the practical synthesis methods to the characterization tools. The book also covers modern applications of nanoalloys in materials science, catalysis or nanomedicine and discusses their possible toxicity. - Covers fundamentals and applicative aspects of nanoalloys in a balanced presentation, including theoretical and experimental perspectives - Describes physical and chemical approaches, synthesis and characterization tools - Illustrates the potential benefit of alloying on various applications ranging from materials science to energy production and nanomedicine - Updates and adds topics not fully developed at the time of the 1st edition, such as toxicity and energy applications
Download or read book Functionalization of Nanoporous Gold with Macrocyclic Metal Complexes a Novel Class of Heterogeneous Singlet Oxygen Photosensitizers written by David Steinebrunner and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the present thesis, the usage of nanoporous gold as support material for immobilization of macrocyclic metal complexes resulting in highly active and truly heterogeneous hybrid photocatalysts was investigated. Such systems are promising photocatalysts for singlet oxygen driven photooxidation reactions as only an appropriate catalyst, oxygen and light are required, offering very mild and sustainable reaction conditions. After optimization of the preparation strategy, the detailed characterization of the obtained novel hybrid materials was a first major point. Including the determination of the pore sizes of the nanoporous gold support, the quantification of the amount of immobilized photosensitizer as well as the distribution over the entire porous structure were studied. By different energy dispersive X-ray mapping and line scanning experiments, a homogeneous distribution of the immobilized metal complex on the porous support was revealed. The photocatalytic investigations of the hybrid photocatalyst can be divided into three sections, which will be also represented in the structure of the present work. The first main focus was the investigation of the structure-activity relationship originating from immobilization onto the nanoporous gold support. Employing the photooxidation of 1,3-diphenylisobenzofuran as model reaction, the hybrid system was investigated in terms of the macroscopic and microscopic properties of the porous support. The macroscopic shapes included the functionalization and comparison of disks, powders and foil-based coatings. The major differences in photocatalytic activity were found as result of the differences in light exposed surface area. In addition, in case of the nanoporous gold coatings the variation of the pore sizes revealed a correlation of the specific surface area with the amount of immobilized photosensitizer. The differences of the pore sizes also allowed the investigation of mass transport as well as diffusion limitation phenomena. Regarding the linking self-assembled monolayer, the necessity of an additional spacer molecule was also investigated by comparison of hybrid systems based on monomolecular and bimolecular monolayers as linking units. The second and most extensive part of this work was the investigation of the underlying photophysical energy transfer processes and interactions between the gold support and the immobilized photosensitizer. For this purpose, the hybrid photocatalyst was irradiated with different excitation wavelengths resulting in action spectra for singlet oxygen formation indicating also singlet oxygen formation by irradiation of the nanoporous gold surface plasmon resonance. Based on those results a reaction mechanism was proposed including energy transfer from the gold support to the attached photosensitizer. The variation of the distance between the two chromophores confirmed the significant contribution of the plasmon resonance within the overall photocatalytic mechanism. Whereas for short distances photoinduced electron transfer from the excited photosensitizer to the support is dominant, for longer distances above 1 nm energy transfer becomes increasingly important. The ideal distance between the two chromophores was found to be around 1.5 nm. Within this study, the impact of the photosensitizer orientation was also investigated and was shown to play a crucial role for the overall distance. Based on those findings, the influence of peripheral and axial linkage was studied employing different classes of photosensitizers ranging from phthalocyanines and tetraphenylporphyrins to axial substituted subphthalocyanines. The variation of the immobilized macrocyclic metal complex can also be seen as first step towards a panchromatic hybrid photocatalyst absorbing light over the entire electromagnetic spectrum of visible light. The last part of the work was focussing on the versatility and predictability of the hybrid system in various photocatalytic oxidation reactions. Here, the novel hybrid photocatalyst was employed in photooxidation reactions of different furan, anthracene and 1,3-cyclohexadiene based derivatives. The results revealed a strong dependency on the used solvent as result of different singlet oxygen lifetimes and diffusion lengths within the porous network. Nevertheless, the entire reactivity of the scope could be predicted from homogeneous liquid-phase reaction rates available in literature considering the employed solvent. Finally, the reusability of the hybrid photocatalyst was examined to show the versatility of this novel system and to give a complete overview of all relevant properties and requirements addressed within the context of applicable truly heterogeneous catalysts.
Download or read book Nanostructured and Advanced Materials for Fuel Cells written by San Ping Jiang and published by CRC Press. This book was released on 2013-12-07 with total page 614 pages. Available in PDF, EPUB and Kindle. Book excerpt: Boasting chapters written by leading international experts, Nanostructured and Advanced Materials for Fuel Cells provides an overview of the progress that has been made so far in the material and catalyst development for fuel cells. The book covers the most recent developments detailing all aspects of synthesis, characterization, and performance. It offers an overview on the principles, classifications, and types of fuels used in fuel cells, and discusses the critical properties, design, and advances made in various sealing materials. It provides an extensive review on the design, configuration, fabrication, modeling, materials, and stack performance of μ-SOFC technology, and addresses the advancement and challenges in the synthesis, characterization, and fundamental understanding of the catalytic activity of nitrogen-carbon, carbon, and noncarbon-based electro catalysts for PEM fuel cells. The authors explore the atomic layer deposition (ALD) technique, summarize the advancements in the fundamental understanding of the most successful Nafion membranes, and focus on the development of alternative and composite membranes for direct alcohol fuel cells (DAFCs). They also review current challenges and consider future development in the industry. Includes 17 chapters, 262 figures, and close to 2000 references Provides an extensive review of the carbon, nitrogen-carbon, and noncarbon-based electro catalysts for fuel cells Presents an update on the latest materials development in conventional fuel cells and emerging fuel cells This text is a single-source reference on the latest advances in the nano-structured materials and electro catalysts for fuel cells, the most efficient and emerging energy conversion technologies for the twenty-first century. It serves as a valuable resource for students, materials engineers, and researchers interested in fuel cell technology.
Download or read book Multifunctional Materials written by Challa Kumar and published by Walter de Gruyter GmbH & Co KG. This book was released on 2020-03-23 with total page 305 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the second volume in the series of books covering practical aspects of synthesis and characterization of various categories of nanomaterials taking into consideration the most up to date research publications. The aim of the book series is to provide students and researchers practical information such as synthetic procedures, characterization protocols and mechanistic insights to enable them to either reproduce well established methods or plan for new syntheses of size and shaped controlled nanomaterials. The second volume focuses on multifunctional nanomaterials.
Download or read book Recent Advances in Nanoparticle Catalysis written by Piet W.N.M. van Leeuwen and published by Springer Nature. This book was released on 2020-07-01 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides an overview of the latest developments in the field of nanoparticle catalysis. It not only discusses established topics in detail, but also explores several emerging topics. Catalysis with nanoparticles is expanding exponentially and is attracting significant interest due to the many exciting findings being reported. Mastering the synthesis, characterization, stabilization and use of these catalysts offers numerous possibilities that far exceed those of classic heterogeneous and homogeneous catalysis.
Download or read book Noble Metal Metal Oxide Hybrid Nanoparticles written by Satyabrata Mohapatra and published by Elsevier. This book was released on 2018-10-11 with total page 675 pages. Available in PDF, EPUB and Kindle. Book excerpt: Noble Metal-Metal Oxide Hybrid Nanoparticles: Fundamentals and Applications sets out concepts and emerging applications of hybrid nanoparticles in biomedicine, antibacterial, energy storage and electronics. The hybridization of noble metals (Gold, Silver, Palladium and Platinum) with metal-oxide nanoparticles exhibits superior features when compared to individual nanoparticles. In some cases, metal oxides act as semiconductors, such as nano zinc oxide or titanium oxide nanoparticles, where their hybridization with silver nanoparticles, enhanced significantly their photocatalytic efficiency. The book highlights how such nanomaterials are used for practical applications. - Examines the properties of metal-metal oxide hybrid nanoparticles that make them so adaptable - Explores the mechanisms by which nanoparticles interact with each other, showing how these can be exploited for practical applications - Shows how metal oxide hybrid nanomaterials are used in a range of industry sectors, including energy, the environment and healthcare
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 Functionalized Nanomaterials Based Devices for Environmental Applications written by Sudheesh K. Shukla and published by Elsevier. This book was released on 2021-08-06 with total page 414 pages. Available in PDF, EPUB and Kindle. Book excerpt: Environmental devices help in monitoring the collection of one or more measurements that are used to access the status of an environment. Today, environmental monitoring and analytical methods are among the most rapidly developing branches of analysis. The functionalization of nanomaterials in the field of environmental science has increasing importance with regards to the fabrication of devices. Functionalized nanomaterials reformulate new materials and advanced characteristics for improved application in comparison to old fashion materials and open an opportunity for the development of devices for introducing new technology and techniques for monitoring environmental challenges. The monitoring of these environmental challenges in advances have direct impact on health and sustainability. Functionalized nanomaterials have different mechanical, absorption, optical or electrical properties than original nanomaterials. In fact, major utilization of nanomaterials occurs in their functionalized forms, which are very different from the parent material. This handbook provides an overview of the different state-of-the-art materials, devices and environmental applications of functionalized nanomaterials. In addition, the information offers a platform for ongoing research in the field of environmental science and device fabrication. The main objective of this book is to cover the major areas focusing on the functionalization of nanomaterials, device fabrication along with different techniques and environmental applications of functionalized nanomaterials-based devices. This is an important reference source for materials scientists, engineers and environmental scientsts who are looking to increase their understanding of how functionalized nanomaterial-based devices are being used for environmental monitoring applications. - Helps the reader to understand the basic principles of functionalization of nanomaterials - Highlights fabrication and characterization methods for functionalized nanomaterials-based environmental monitoring devices - Assesses the major challenges of creating devices using functionalized nanomaterials on a mass scale
Download or read book Encyclopedia of Interfacial Chemistry written by and published by Elsevier. This book was released on 2018-03-29 with total page 5276 pages. Available in PDF, EPUB and Kindle. Book excerpt: Encyclopedia of Interfacial Chemistry: Surface Science and Electrochemistry, Seven Volume Set summarizes current, fundamental knowledge of interfacial chemistry, bringing readers the latest developments in the field. As the chemical and physical properties and processes at solid and liquid interfaces are the scientific basis of so many technologies which enhance our lives and create new opportunities, its important to highlight how these technologies enable the design and optimization of functional materials for heterogeneous and electro-catalysts in food production, pollution control, energy conversion and storage, medical applications requiring biocompatibility, drug delivery, and more. This book provides an interdisciplinary view that lies at the intersection of these fields. Presents fundamental knowledge of interfacial chemistry, surface science and electrochemistry and provides cutting-edge research from academics and practitioners across various fields and global regions
Download or read book Functionalized Nanomaterial Based Electrochemical Sensors written by Jamballi G. Manjunatha and published by Woodhead Publishing. This book was released on 2022-01-11 with total page 612 pages. Available in PDF, EPUB and Kindle. Book excerpt: Functionalized Nanomaterial-Based Electrochemical Sensors: Principles, Fabrication Methods, and Applications provides a comprehensive overview of materials, functionalized interfaces, fabrication strategies and application areas. Special attention is given to the remaining challenges and opportunities for commercial realization of functionalized nanomaterial-based electrochemical sensors. An assortment of nanomaterials has been investigated for their incorporation into electrochemical sensors. For example, carbon- based nanomaterials (carbon nanotube, graphene and carbon fiber), noble metals (Au, Ag and Pt), polymers (nafion, polypyrrole) and non-noble metal oxides (Fe2O3, NiO, and Co3O4). The most relevant materials are discussed in the book with an emphasis on their evaluation of their realization in commercial applications. Application areas touched on include the environment, food and medicine industries. Health, safety and regulation considerations are touched on, along with economic and commercialization trends. - Introduces the principles of nanomaterials for electrochemical sensing applications - Reviews the most relevant fabrication strategies for functionalized nanomaterial-based electrochemical sensing platforms - Discusses considerations for the commercial realization of functionalized nanomaterial-based electrochemical sensors in the environment, food and point-of-care applications
Download or read book Introduction to Nanoporous Gold written by and published by . This book was released on 2011 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nanomechanical and Scaling Behavior of Nanoporous Gold written by Nicolas Jérôme Briot and published by . This book was released on 2015 with total page 179 pages. Available in PDF, EPUB and Kindle. Book excerpt:
