Download or read book A Surfactant free Strategy for Synthesizing and Processing Intermetallic Platinum based Nanoparticle Catalysts written by Hao Chen and published by . This book was released on 2013 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, a surfactant-free Np-KCl matrix method (Np stands for nanoparticle, KCl is potassium chloride) is developed for the synthesis of nanoparticles with controlled size and structure. In this method, a Np-KCl composite is formed in a onepot reduction in THF at room temperature. KCl is an insoluble by-product of the reaction and serves as a matrix that traps the nanoparticles to avoid particle agglomeration and to control the coalescence of nanoparticles during thermal annealing up to 600 oC. By varying the molar ratio of metal precursors and KCl, as well as the time and temperature of annealing, the final particle sizes and crystalline order can be independently controlled. After thermal processing, nanoparticles can be released from the KCl matrix in an ethylene glycol-water solution and transferred to support materials forming a uniform Np-support composite. An in-situ STEM (scanning transmission electron microscope) study revealed that the mechanism of nanoparticle growth during annealing is dominated by particle-particle coalescence, although Ostwald ripening also occurs at a slower rate. A detailed study of the synthesis of ordered intermetallic Pt3Fe and PtFe nanoparticles with an average diameter of 4 nm is provided as two examples of the method. The generality of the method was extended to synthesis of other bi- and tri-metallic nanoparticles of platinum transition metal compounds. We expect that a wide variety of non-Pt metal containing nanoparticles can be also prepared using this same approach.
Download or read book A Ship in a bottle Strategy to Synthesize Encapsulated Intermetallic Nanoparticle Catalysts written by and published by . This book was released on 2016 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this paper, intermetallic compounds are garnering increasing attention as efficient catalysts for improved selectivity in chemical processes. Here, using a ship-in-a-bottle strategy, we synthesize single-phase platinum-based intermetallic nanoparticles (NPs) protected by a mesoporous silica (mSiO2) shell by heterogeneous reduction and nucleation of Sn, Pb, or Zn in mSiO2-encapsulated Pt NPs. For selective hydrogenation of furfural to furfuryl alcohol, a dramatic increase in activity and selectivity is observed when intermetallic NPs catalysts are used in comparison to Pt@mSiO2. Among the intermetallic NPs, PtSn@mSiO2 exhibits the best performance, requiring only one-tenth of the quantity of Pt used in Pt@mSiO2 for similar activity and near 100% selectivity to furfuryl alcohol. A high-temperature oxidation-reduction treatment easily reverses any carbon deposition-induced catalyst deactivation. X-ray photoelectron spectroscopy shows the importance of surface composition to the activity, whereas density functional theory calculations reveal that the enhanced selectivity on PtSn compared to Pt is due to the different furfural adsorption configurations on the two surfaces.
Download or read book Nanostructured intermetallics from rational synthesis to energy electrocatalysis written by Mingcheng Zhang and published by OAE Publishing Inc.. This book was released on 2023-06-05 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: Intermetallics are a large family of structurally ordered alloys that combines a metal element with other metal/metalloid elements with a clearly defined stoichiometric ratio. Intermetallics possess abundant crystal structures and atomic packing motifs, giving rise to a great variety of electronic configurations and surface adsorption properties. The wide electronic and geometric diversity makes intermetallics a highly promising population for discovering advanced materials for various catalytic applications. This review presents recent advances in the reaction synthesis of intermetallic materials at the nanoscale and their energy-related electrocatalytic applications. Initially, we introduce general principles for the formation of stable intermetallic structures. Subsequently, we elaborate on common synthetic strategies of nanostructured intermetallics, such as thermal annealing, wet-chemical methods, metallothermic reduction, and template-directed synthesis. Furthermore, we discuss the wide employment of these intermetallic nanocatalysts in many different kinds of electrocatalytic applications, as well as highlight the theoretical and experimental evidence for establishing a reasonable relationship between atomic arrangement and catalytic activity. Finally, we propose some perspectives for future developments of intermetallic preparation and catalytic applications.
Download or read book Controlled Synthesis of Pt Ni Bimetallic Catalysts and Study of Their Catalytic Properties written by Yuen Wu and published by Springer. This book was released on 2016-05-14 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis focuses on the controlled synthesis of Pt–Ni bimetallic nanoparticles and the study of their catalytic properties. It discusses in detail the nucleation mechanism and the growth process of bimetallic systems, which is vital for a deeper understanding of the design of bimetallic catalysts. The author presents four pioneering studies: (1) syntheses of water-soluble octahedral, truncated octahedral, and cubic Pt–Ni nanocrystals and the study of their structure-activity relationship in model hydrogenation reactions; (2) a strategy for designing a concave Pt–Ni alloy using controllable chemical etching; (3) defect-dominated shape recovery of nanocrystals, which is a new synthesis strategy for trimetallic catalysts; (4) a sophisticated construction of Au islands on Pt−Ni, which is an ideal trimetallic nanoframe catalyst. This thesis inspires researchers working in materials, catalysis as well as other interdisciplinary areas.
Download or read book Bimetallic Nanostructures written by Ya-Wen Zhang and published by John Wiley & Sons. This book was released on 2018-08-06 with total page 521 pages. Available in PDF, EPUB and Kindle. Book excerpt: Systematically summarizes the current status and recent advances in bimetallic structures, their shape-controlled synthesis, properties, and applications Intensive researches are currently being carried out on bimetallic nanostructures, focusing on a number of fundamental, physical, and chemical questions regarding their synthesis and properties. This book presents a systematic and comprehensive summary of the current status and recent advances in this field, supporting readers in the synthesis of model bimetallic nanoparticles, and the exploration and interpretation of their properties. Bimetallic Nanostructures: Shape-Controlled Synthesis for Catalysis, Plasmonics and Sensing Applications is divided into three parts. Part 1 introduces basic chemical and physical knowledge of bimetallic structures, including fundamentals, computational models, and in situ characterization techniques. Part 2 summarizes recent developments in synthetic methods, characterization, and properties of bimetallic structures from the perspective of morphology effect, including zero-dimensional nanomaterials, one-dimensional nanomaterials, and two-dimensional nanomaterials. Part 3 discusses applications in electrocatalysis, heterogeneous catalysis, plasmonics and sensing. Comprehensive reference for an important multidisciplinary research field Thoroughly summarizes the present state and latest developments in bimetallic structures Helps researchers find optimal synthetic methods and explore new phenomena in surface science and synthetic chemistry of bimetallic nanostructures Bimetallic Nanostructures: Shape-Controlled Synthesis for Catalysis, Plasmonics and Sensing Applications is an excellent source or reference for researchers and advanced students. Academic researchers in nanoscience, nanocatalysis, and surface plasmonics, and those working in industry in areas involving nanotechnology, catalysis and optoelectronics, will find this book of interest.
Download or read book Synthesis of Platinum Intermetallic Compounds for Fuel Cell Anode Catalysts written by Laif Robert Alden and published by . This book was released on 2006 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Electrocatalysis in Fuel Cells written by Minhua Shao and published by Springer Science & Business Media. This book was released on 2013-04-08 with total page 748 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fuel cells are one of the most promising clean energy conversion devices that can solve the environmental and energy problems in our society. However, the high platinum loading of fuel cells - and thus their high cost - prevents their commercialization. Non- or low- platinum electrocatalysts are needed to lower the fuel cell cost. Electrocatalysis in Fuel Cells: A Non and Low Platinum Approach is a comprehensive book summarizing recent advances of electrocatalysis in oxygen reduction and alcohol oxidation, with a particular focus on non- and low-Pt electrocatalysts. All twenty four chapters were written by worldwide experts in their fields. The fundamentals and applications of novel electrocatalysts are discussed thoroughly in the book. The book is geared toward researchers in the field, postgraduate students and lecturers, and scientists and engineers at fuel cell and automotive companies. It can even be a reference book for those who are interested in this area.
Download or read book Synthesis of Platinum Based Nanocatalysts with Controlled Particle Parameters and Study for Their Properties in Oxidation Reactions written by Sang Youp Hwang and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Controllable nanoparticles with different morphology, alloy, composition, and sizes were investigated and analyzed. The nanoparticles, which act as a catalyst, are synthesized using solid state and wet chemistry method. The synthesized catalysts also were demonstrated for the various chemical reactions, such as CO oxidation and CO preferential oxidation (PROX). Group VIII metal nanoparticles with variant morphologies are synthesized under carbon monoxide atmosphere. The important roles of CO in determining the surface formation of growing particles are studied by both experiments and density functional theory calculations, which suggest different growth mechanisms for these metals. Alumina-supported platinum-silver alloy nanoparticle (Pt-Ag/Al2O3) catalysts have been prepared using a wet chemistry method and studied for the property in carbon monoxide oxidation reaction. The Pt-Ag alloy catalyst exhibits significantly improved activity and largely decreased activation energy barrier comparing to both pure Pt and pure Ag catalysts in the room temperature range. The Langmuir-Hinshelwood mechanism, in which surface Pt active sites chemisorb CO and adjacent Ag sites activate O2, was proposed and discussed for explaining the promoted CO oxidation kinetics on the Pt-Ag alloy. Octahedral Pt3Ni alloy nanoparticles on carbon and alumina supports are prepared and tested for CO preferential oxidation (PROX) in H2. Both catalysts exhibit much superior PROX property with high activity and 100% selectivity between around RT and 100 °C. The improved activity of the octahedral Pt3Ni has been attributed to bifunctional sites mechanism. The excellent selectivity is correlated with the unique surface geometry and electronic structure of the octahedral Pt3Ni. Pt/SiO2 catalysts with different Pt nanoparticle size are prepared using an impregnation method. The 2.4 nm Pt/SiO2 exhibits improved CO oxidation activity and turnover frequency (TOF) comparing to either bigger or smaller Pt catalysts. The different catalytic activities are related with the adsorption energy, which is caused by the different electronic structure such as d-band center and work function. Cubic and spherical PtMn alloy nanoparticles on alumina were synthesized and tested for CO preferential oxidation (PROX). Both catalysts exhibited 100% CO selectivity in a wide temperature window. The extended temperature windows for CO PROX on PtMn have been attributed to a low reducibility of Mn oxide. The findings of high selectivity in a broad temperature window were confirmed using various Pt alloy catalysts with a different reducibility of surface oxide.
Download or read book Mesoporous Zeolites written by Javier García-Martínez and published by John Wiley & Sons. This book was released on 2015-05-26 with total page 608 pages. Available in PDF, EPUB and Kindle. Book excerpt: Authored by a top-level team of both academic and industrial researchers in the field, this is an up-to-date review of mesoporous zeolites. The leading experts cover novel preparation methods that allow for a purpose-oriented fine-tuning of zeolite properties, as well as the related materials, discussing the specific characterization methods and the applications in close relation to each individual preparation approach. The result is a self-contained treatment of the different classes of mesoporous zeolites. With its academic insights and practical relevance this is a comprehensive handbook for researchers in the field and related areas, as well as for developers from the chemical industry.
Download or read book The Synthesis Characterization and Catalytic Reaction Studies OfMonodisperse Platinum Nanoparticles in Mesoporous Oxide Materials written by Robert M. Rioux and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Laser Ablation in Liquids written by Guowei Yang and published by CRC Press. This book was released on 2012-02-22 with total page 1166 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on the fundamental concepts and physical and chemical aspects of pulsed laser ablation of solid targets in liquid environments and its applications in the preparation of nanomaterials and fabrication of nanostructures. The areas of focus include basic thermodynamic and kinetic processes of laser ablation in liquids, and its applic
Download or read book La boda cambiada written by and published by . This book was released on 1809 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis of Platinum Nanoparticles and Their Use in Novel Heterogeneous Catalysts written by Jonathan E. Sutton and published by . This book was released on 2007 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Controlling the Growth and Catalytic Activity of Platinum Nanoparticles Using Peptide and Polymer Ligands written by Lauren Marie Forbes and published by . This book was released on 2013 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: Heterogeneous catalysts have widespread industrial applications. Platinum nanomaterials in particular, due to their particularly high electrocatalytic activity and durability, are used to catalyze a wide variety of reactions, including oxygen reduction, which is frequently used as the cathode reaction in fuel cells. As platinum is a very expensive material, a high priority in fuel cell research is the exploration of less expensive, more efficient catalysts for the oxygen reduction reaction (ORR). We demonstrate here the use of phage display to identify peptides that bind to Pt (100) which were then used to synthesize platinum cubes in solution. However, while the peptides were able to control particle growth, the bio-synthesized Pt particles showed extremely poor activity when tested for ORR. This could be attributed to peptide coverage on the surface or strong interactions between particular amino acids and the metal that are detrimental for catalysis. To investigate this further, we decided to investigate the role of individual amino acids on Pt nanocrystal synthesis and catalysis. For this, we conjugated the R-groups of single amino acids to polyethylene glycol (PEG) chains. Through this work we have determined that the identity of the amino acid R-group is important in both the synthesis and the catalytic activity of the particles. For Pt nanoparticle synthesis, we found that the hydrophobicity of the functional groups affected their ability to interact well with the particles during nucleation and growth, and thus only the hydrophilic functional groups were capable of mediating the synthesis to produce well-defined faceted particles. With respect to ORR, we found distinct trends that showed that the inclusion of certain amino acids could significantly enhance catalysis- even at high polymer loadings. This work presents evidence that counters the common conception that organic capping ligands decrease catalytic activity; in fact activity may actually be improved over bare metal through judicious choice and design of ligands that inhibit Pt oxidation and control chain packing at the Pt surface. Therefore, it may be possible to have ligands on a nanoparticle surface that allow the particles to be well-dispersed on an electrode surface, while simultaneously enhancing catalysis.
Download or read book Underneath the Bragg Peaks written by Takeshi Egami and published by Elsevier. This book was released on 2003-10-02 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: Table of contents
Download or read book Nanoparticulate Materials written by Kathy Lu and published by John Wiley & Sons. This book was released on 2012-09-25 with total page 379 pages. Available in PDF, EPUB and Kindle. Book excerpt: Serving as the only systematic and comprehensive treatment on the topic of nanoparticle-based materials, this book covers synthesis, characterization, assembly, shaping and sintering of all types of nanoparticles including metals, ceramics, and semiconductors. A single-authored work, it is suitable as a graduate-level text in nanomaterials courses.
Download or read book Nanocatalysis written by Vivek Polshettiwar and published by John Wiley & Sons. This book was released on 2013-09-06 with total page 670 pages. Available in PDF, EPUB and Kindle. Book excerpt: Exhibiting both homogeneous and heterogeneous catalytic properties, nanocatalysts allow for rapid and selective chemical transformations, with the benefits of excellent product yield and ease of catalyst separation and recovery. This book reviews the catalytic performance and the synthesis and characterization of nanocatalysts, examining the current state of the art and pointing the way towards new avenues of research. Moreover, the authors discuss new and emerging applications of nanocatalysts and nanocatalysis, from pharmaceuticals to fine chemicals to renewable energy to biotransformations. Nanocatalysis features contributions from leading research groups around the world. These contributions reflect a thorough review of the current literature as well as the authors’ first-hand experience designing and synthesizing nanocatalysts and developing new applications for them. The book’s nineteen chapters offer a broad perspective, covering: Nanocatalysis for carbon-carbon and carbon-heteroatom coupling reactions Nanocatalysis for various organic transformations in fine chemical synthesis Nanocatalysis for oxidation, hydrogenation, and other related reactions Nanomaterial-based photocatalysis and biocatalysis Nanocatalysts to produce non-conventional energy such as hydrogen and biofuels Nanocatalysts and nano-biocatalysts in the chemical industry Readers will also learn about the latest spectroscopic and microscopy tools used in advanced characterization methods that shed new light on nanocatalysts and nanocatalysis. Moreover, the authors offer expert advice to help readers develop strategies to improve catalytic performance. Summarizing and reviewing all the most important advances in nanocatalysis over the last two decades, this book explains the many advantages of nanocatalysts over conventional homogeneous and heterogeneous catalysts, providing the information and guidance needed for designing green, sustainable catalytic processes.
