Carbon-Supported Transition Metal Nanoparticles for Catalytic and Electromagnetic Applications PDF Download
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Author:
Publisher:
ISBN:
Category : Catalysis
Languages : en
Pages : 110
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Book Description
Recently, there has been growing interest in using transition metals (TM) for catalytic and electromagnetic applications, due to the ability of TMs to form stable compounds in multiple oxidation states. In this research, the focus has been on the synthesis and characterization of carbon-supported TM nanoparticles (NPs), specifically palladium (Pd) and gold (Au) NPs, for catalytic applications, and transition metal oxides (TMO) NPs, specifically Fe3O4 NPs for electromagnetic applications. Carbon supports have several advantages, such as enabling even distribution of particles, offering large specific surface area with excellent electron conductivity, and relative chemical inertness. In this dissertation, for catalytic applications, emphasis was on removal of trichloroethylene (TCE) from groundwater. For this application, carbon-supported Pd/Au NP catalysts were developed. Pd was chosen because it is more active, stable and selective for desired end-products, and Au has shown to be a good promotor of Pd's catalytic activity. Often, commercially available Pd-based catalysts are made using harsh chemicals, which can be harmful to the environment. Here, an environmentally friendly process with aspects of green chemistry was developed to produce carbon-supported Pd/Au NP catalysts. This process uses a combination of sonochemistry and solvothermal syntheses. The carefully designed carbon-supported Pd/Au NP catalyst material was systematically characterized, tested against TCE, and optimized for increased rate of removal of TCE. Electron microscopy and spectroscopy techniques were used to study the material including structure, configuration and oxidative state. The Pd/Au NPs were found mainly to form clusters with an aggregate-PdShellAuCore structure. Using state-of-the-art direct detection with electron energy loss spectroscopy, the Pd NPs were found to have an oxidative state of zero (0). The formation of the catalyst material was studied in detail by varying several synthesis parameters including type of solvent, sonication time, synthesis temperature etc. The most optimized catalyst was found remove TCE at double the rate of corresponding commercial Pd-based catalysts in a hydrogen headspace. This material was found to catalyze the removal of TCE via traditional hydrodehalogenation and shows promise for the removal of other contaminants such as trichloropropane (TCP), carbon tetrachloride (CT). The focus of this dissertation was on the development of a methodology for carbon-supported TM and TMO NPs for specific applications. It is envisioned that this approach and strategy will contribute towards the future optimization of similar material systems for a multitude of applications.
Author:
Publisher:
ISBN:
Category : Catalysis
Languages : en
Pages : 110
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Book Description
Recently, there has been growing interest in using transition metals (TM) for catalytic and electromagnetic applications, due to the ability of TMs to form stable compounds in multiple oxidation states. In this research, the focus has been on the synthesis and characterization of carbon-supported TM nanoparticles (NPs), specifically palladium (Pd) and gold (Au) NPs, for catalytic applications, and transition metal oxides (TMO) NPs, specifically Fe3O4 NPs for electromagnetic applications. Carbon supports have several advantages, such as enabling even distribution of particles, offering large specific surface area with excellent electron conductivity, and relative chemical inertness. In this dissertation, for catalytic applications, emphasis was on removal of trichloroethylene (TCE) from groundwater. For this application, carbon-supported Pd/Au NP catalysts were developed. Pd was chosen because it is more active, stable and selective for desired end-products, and Au has shown to be a good promotor of Pd's catalytic activity. Often, commercially available Pd-based catalysts are made using harsh chemicals, which can be harmful to the environment. Here, an environmentally friendly process with aspects of green chemistry was developed to produce carbon-supported Pd/Au NP catalysts. This process uses a combination of sonochemistry and solvothermal syntheses. The carefully designed carbon-supported Pd/Au NP catalyst material was systematically characterized, tested against TCE, and optimized for increased rate of removal of TCE. Electron microscopy and spectroscopy techniques were used to study the material including structure, configuration and oxidative state. The Pd/Au NPs were found mainly to form clusters with an aggregate-PdShellAuCore structure. Using state-of-the-art direct detection with electron energy loss spectroscopy, the Pd NPs were found to have an oxidative state of zero (0). The formation of the catalyst material was studied in detail by varying several synthesis parameters including type of solvent, sonication time, synthesis temperature etc. The most optimized catalyst was found remove TCE at double the rate of corresponding commercial Pd-based catalysts in a hydrogen headspace. This material was found to catalyze the removal of TCE via traditional hydrodehalogenation and shows promise for the removal of other contaminants such as trichloropropane (TCP), carbon tetrachloride (CT). The focus of this dissertation was on the development of a methodology for carbon-supported TM and TMO NPs for specific applications. It is envisioned that this approach and strategy will contribute towards the future optimization of similar material systems for a multitude of applications.
Author: Nazgol Norouzi
Publisher:
ISBN:
Category : Catalysts
Languages : en
Pages : 184
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Book Description
Precise control of metal nanoparticles' size, composition, and dispersity over high surface area supports are highly desirable to address current challenges in energy storage and conversion as well as catalytic processes involving precious metals. Therefore, developing viable synthetic routes that enable new catalytic systems derived from inexpensive transition metals or limited use of precious metals is vital for clean energy applications such as fuel cells and rechargeable batteries or affordable drugs in the pharmaceuticals arena. In addition to metal components of heterogeneous catalysts, the catalyst support is an integral part of catalyst design as it can impart both physical stability and catalytic enhancement through strong metal-support interactions. In particular, recent studies have shown that the incorporation of heteroatoms like nitrogen and phosphorus in high surface area carbon supports is an effective approach for tailoring the textural and electronic properties of carbon supports. Here we introduce different supported metal nanoparticles on high surface area supports, with their characteristic tuned toward different applications. In the first project, we developed an iron phosphide doped porous carbon system (PFeC) and used it as a cathode catalyst for oxygen reduction reaction (ORR) in fuel cells. The conversion of chemical energy to electrical energy is a sustainable approach for energy production achieved by fuel cells. Currently, the noble metal platinum, in the form of 20 wt% Pd deposited on carbon support (Pt/C) is the commercially available catalyst for the ORR. Sluggish ORR mechanism and lack of long-term stability demand for a more sustainable, inexpensive, and kinetically efficient replacement catalyst. Here iron phosphide nanoparticles (NPs) incorporated in a phosphorus-doped porous carbon, with a high specific area (SABET = 967 m2 g−1) was synthesized using inexpensive reactants, triphenylphosphine and iron chloride by a facile carbonization/chemical activation method via zinc chloride. PFeC selectively reduces O2 via an efficient reaction pathway and exhibits superior long-term stability than Pt/C. The superior electrocatalytic performance is credited to the synergistic effects between the P and Fe which, form well-defined and well-distributed nanoparticles confined in highly porous carbon nanosheets. In the second project, supported palladium-based ultra-small bimetallic NPs deposited on mesoporous fumed silica support (SABET = 350 m2 g−1) were synthesized and used as a catalyst for Suzuki -Miyaura cross-coupling (SCC) reactions. Bimetallic NPs consisting of active metal Pd and base metals (Cu, Ni, and Co) were deposited on the silica support through strong electrostatic (SEA) synthesis method yielding homogeneously alloyed nanoparticles with an average size of 1.3 nm. All bimetallic catalysts were found to be highly active toward SCC surpassing the activity of monometallic Pd/SiO2. In particular, the catalyst consisting of Cu and Pd (CuPd/SiO2), performed the SCC with a remarkable turn over frequency of 248000. The combination of Pd with base metals helps in retaining the Pd0 status by charge donation from base metals to Pd and thus facilitating the SCC, in specific lowering the activation energy of the aryl halide oxidative addition rate-limiting step. In the third and last project, functionalized supports are widely utilized in energy conversion and energy storage applications. High surface area porous carbon materials have been introduced as a highly active cathode material for Lithium-sulfur batteries (LSB). The electrochemical performance of the LSB can be largely improved by the efficient reversible conversion of lithium polysulfides to Li2S during discharge and to elemental sulfur during charge. Nickel NPs deposited on high surface area nitrogen-doped carbon support (Ni/BIDC-900, SABET = 3560 m2 g−1) act as active centers for the adsorption of polysulfides during the discharge process and rapidly convert them to Li2S while catalyzing Li2S oxidation to sulfur in the reverse process. The addition of Ni NPs improves the reaction kinetics and activity retention of the LSB.
Author: Bing Zhou
Publisher: Springer Science & Business Media
ISBN: 9780306483233
Category : Science
Languages : en
Pages : 416
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Book Description
This book is mainly based on the first and second symposia on Nanotechnology in Catalysis held in 2001 and 2002, but it also includes several contributions not presented in the symposia to round out the scope of the subject. The contents are the most up to date developments made by researchers all over the world in the catalysis field in this fascinating nanotechnology era. It reflects some of the frontier areas of nanoscience and nanotechnology in fabricating and characterizing catalysts and carrying out studies to prove their superior selectivity and activity. The field of application of nanotechnology for the development of catalysts for green chemistry is likely to grow rapidly during the next decade. This book hopes to contribute to the evolution of nanotechnology in that direction.
Author: Jia-Nan Zhang
Publisher: Springer Nature
ISBN: 9811946256
Category : Technology & Engineering
Languages : en
Pages : 288
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Book Description
This book systematically summarizes the advanced development of carbon-based nanomaterials for electrochemical catalysis, and it is comprised of four sections. The first section discusses about the fundamental synthesis, characterization techniques, and catalytic effects on the energy conversion and storage mechanism. The second section elaborately reviews various types of electrocatalytic reactions on carbon-based materials and their performance. The third section focuses on batteries about carbon-based materials with different storage mechanism. And the last one, the following enlightenment in terms of theoretical development and experimental research is provided to the general readers: 1) Precise design and construction of local atomic and electronic structures at the interface of catalysts; 2) Selective activation and directed conversion of carbon-based energy-carrying molecules at the interface; 3) Interaction mechanism and regulation of catalyst solid surface interface properties under environment and external field. This book will be useful for researchers and students who are interested in carbon-based nanomaterials, electrochemical catalysts and energy storage.
Author: Bert Sels
Publisher: John Wiley & Sons
ISBN: 352769983X
Category : Technology & Engineering
Languages : en
Pages : 1500
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Book Description
Reflecting the R&D efforts in the field that have resulted in a plethora of novel applications over the past decade, this handbook gives a comprehensive overview of the tangible benefits of nanotechnology in catalysis. By bridging fundamental research and industrial development, it provides a unique perspective on this scientifically and economically important field. While the first three parts are devoted to preparation and characterization of nanocatalysts, the final three provide in-depth insights into their applications in the fine chemicals industry, the energy industry, and for environmental protection, with expert authors reporting on real-life applications that are on the brink of commercialization. Timely reading for catalytic chemists, materials scientists, chemists in industry, and process engineers.
Author: Franklin (Feng) Tao
Publisher: Royal Society of Chemistry
ISBN: 1782620338
Category : Science
Languages : en
Pages : 285
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Book Description
An introduction to the synthesis and applications of different nanocatalysts.
Author: Ashish Kumar Mishra
Publisher: World Scientific
ISBN: 9811283419
Category : Technology & Engineering
Languages : en
Pages : 313
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Book Description
The world's increasing demand for energy is mainly being fulfilled by non-renewable fossil fuels. Its long-run usage is unsustainable due to depleting resources and adverse effects on the environment. To resolve these issues, researchers are transitioning toward high-performance renewable and sustainable energy sources and storage systems like electrochemical cells for hydrogen production, supercapacitors, batteries, and so forth. Currently, the main challenges to developing these systems require efficient electrode materials with properties like good electrical conductivity, high surface area, good catalytic activity, and so on. Carbon nanostructures (such as graphene and carbon nanotubes) and inorganic transition metal dichalcogenides (such as MoS2, WS2, MoSe2, etc.) are promising candidates for such energy applications owing to their unique properties and exceptional performance. This book summarizes the synthesis of carbon and TMDs to their applications in energy generation and storage. The aim of this book is to benefit the readers with recent aspects and future perspectives of carbon and TMDs-based nanomaterials dedicated to the field of energy generation and storage technologies. Also, professionals might find it useful in fabricating or characterizing these materials for targeted applications.
Author: Yanjuan Gu
Publisher: Open Dissertation Press
ISBN: 9781361427170
Category :
Languages : en
Pages :
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Book Description
This dissertation, "Nanostructure of Transition Metal and Metal Oxide for Electrocatalysis" by Yanjuan, Gu, 谷艳娟, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of thesis entitled NANOSTRUCTURE OF TRANSITION METAL AND METAL OXIDE FOR ELECTROCATALYSIS Submitted by Gu Yan Juan for the degree of Doctor of Philosophy at The University of Hong Kong in August 2006 Pd, Pt, and Ru nanoparticles that were uniformly dispersed on multi-walled carbon nanotubes (MWNTs) were synthesized by vacuum pyrolysis using metal acetylacetonate as metal precursor, and the nanocomposites were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X- ray diffraction (XRD). The size and distribution of the nanoparticles were strongly affected by the reaction time, temperature, and the initial mass ratio of the metal precursors to MWNTs. The higher temperature, the smaller Pd nanoparticles were formed at the range of 250 to 500 C. The average size of the Pd nanoparticles increased with the increase in mass ratio of the metal precursors to MWNTs. The particle size of Pt and Ru showed little change with the change in mass ratio. Pt and Ru nanoparticles had the mean diameters of 3.00.6 and 2.50.4 nm when the mass ratio of Pt(acac) and Ru(acac) to 2 3 MWNTs was both 2:1 at 500 C. The electrocatalytic activity of Pt/MWNTs and PtRu/MWNTs was investigated at room temperature by cyclic voltammetry and chronoamperometry. All of the electrochemical results showed that the PtRu/MWNTs catalyst exhibit high activity for methanol oxidation that resulted from the high surface area of carbon nanotubes and the platinum/ruthenium nanoparticles. Compared with Pt/MWNTs, the onset potential is much lower and the ratio of forward anodic peak current to reverse anodic peak current is much higher for methanol oxidation. Pt Ru /MWNTs displayed the best electrocatalytic 45 55 activities among all carbon nanotubes supported Pt and PtRu catalysts. Hyperbranched RuO nanostructures can be formed through the oxidation of Ru nanoparticles at relatively low temperatures in air, which is a very simple and low cost method. The morphology of the RuO nanostructure is closely associated with the dispersivity of the Ru nanoparticles on the MWNTs. Cu, Pt and Pd nanoparticles are very effective catalysts in the formation of RuO hyperbranched nanostructures. The electrochemical studies of these nanorods demonstrated that they display characteristic properties of RuO (110) surface. The successful attachment of Pt nanoparticles to RuO surface through a simple, two-step chemically controlled procedure is reported. The effect of the single crystal structure of RuO nanorods on the electrocatalytic activity of Pt nanoparticles was investigated, showing that the presence of the RuO nanorods greatly increases the electrochemical activity of electrodes toward methanol oxidation, not only increasing the current density but also shifting the onset potential of methanol electrooxidation to over 200 mV lower than that on the Pt nanoparticle electrode. The results described here also demonstrate the ability of metal oxide nanorods to serve as a conductive support for fuel cell applications. DOI: 10.5353/th_b3777439 Subjects: Electrocatalysis Transition metals Nanoparticles Nanostructured materials Methanol - Oxidation
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 276
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Book Description
Author: Rafael Luque
Publisher: Royal Society of Chemistry
ISBN: 1849734283
Category : Nature
Languages : en
Pages : 243
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Book Description
This timely publication bridges and presents the latest trends and updates in three hot topics of current and future society: nanomaterials, energy and environment. It provides the state-of-the-art as well as current challenges and advances in the sustainable preparation of metal nanoparticles and their applications. The book fills a critical gap in a multidisciplinary area of high economic, social and environmental importance. Currently, there are no books published that deal with these ever increasing important topics, as most books in this area focus on a particular topic (eg. nanomaterials or catalysis or energy or environment). This is the first multidisciplinary edited book covering the very basics to the more advanced, trendy developments, containing a unique blend of nano, green, renewable and bio.
