Download or read book Preparation of Supported Ruthenium and Platinum Nanoparticles by Supercritical Incorporation Methods written by Ying Zhang and published by . This book was released on 2006 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Investigation of Synthesis Methods for Improved Platinum Ruthenium Nanoparticles Supported on Multi Walled Carbon Nanotube Electrocatalysts for Direct Methanol Fuel Cells written by Lindiwe Eudora Khotseng and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book chapter reports on various catalyst synthesis methods (impregnation, polyol, modified polyol, and microwave-assisted modified polyol methods) to determine which method would result in the most electrochemically active platinum-ruthenium (PtRu) electrocatalyst supported on multi-walled carbon nanotubes (MWCNTs) for methanol oxidation reaction in an acidic medium. Different techniques were used to characterize the synthesized catalysts, including the high-resolution transmission electron microscope used for morphology and calculating particle sizes, and X-ray diffraction for determining crystalline sizes. The electroactive catalyst surface area, ECSA of the electrocatalysts was determined using cyclic voltammetry (CV), while the electroactivity, electron kinetics, and stability of the electrocatalysts towards methanol oxidation were evaluated using CV, electrochemical impedance spectroscopy, and chronoamperometry, respectively. The microwave-assisted modified polyol method produced the PtRu/MWCNT electrocatalyst with the most enhanced electrocatalytic activity compared to other PtRu/MWCNT catalysts produced by the impregnation, polyol, and modified polyol methods.

Download or read book Supercritical Fluids and Organometallic Compounds written by Can Erkey and published by Elsevier. This book was released on 2011-11-22 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: Organometallic compounds are utilized as reagents in the preparation and processing of advanced nanostructured materials, as catalysts in the production of a wide variety of specialty chemicals and polymers, and as drugs. Supercritical fluid science and technology has a wide variety of applications ranging from extraction of pharmaceutically active compounds to the synthesis of advanced materials. The combination of organometallic chemistry and supercritical fluids has significant potential. This book covers the fundamental aspects and related applications in this rapidly growing area. Covers the preparation of nanostructured composite materials using supercritical fluids Focuses on the intersection of organometallic chemistry and supercritical fluids Addresses the behavior of organometallic compounds in supercritical fluid environments

Download or read book Biomass Biofuels Biochemicals written by S. Saravanamurugan and published by Elsevier. This book was released on 2019-10-23 with total page 508 pages. Available in PDF, EPUB and Kindle. Book excerpt: Biomass, Biofuels, Biochemicals: Recent Advances in Development of Platform Chemicals provides a detailed overview on the experimentally developed methods that facilitate platform chemicals derivation from biomass-based substrates with robust catalyst systems. In addition, the book highlights the green chemistry approach towards platform chemical production. Chapters discuss platform chemicals and global market volumes, the optimization of process schemes and reaction parameters with respect to achieving a high yield of targeted platform chemicals, such as sugars and furonic compounds by modifying the respective catalytic system, the influence of solvents on reaction selectivity and product distribution, and the long-term stability of employed catalysts. Overall, the objectives of the book are to provide the reader with an understanding of the societal importance of platform chemicals, an assessment of the techno-economic viability of biomass valorization processes, catalyst design for a specific reaction, and the design of a catalytic system. Covers recent developments on platform chemicals Provides comprehensive technological developments on specific platform chemicals Covers organic transformations, catalytic synthesis, thermal stability, reaction parameters and solvent effect Includes case studies on the production of a number of chemicals, such as Levulinic acid, glycerol, phenol derivatives, and more

Download or read book Platinum Adlayered Ruthenium Nanoparticles Method for Preparing and Uses Thereof written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A superior, industrially scalable one-pot ethylene glycol-based wet chemistry method to prepare platinum-adlayered ruthenium nanoparticles has been developed that offers an exquisite control of the platinum packing density of the adlayers and effectively prevents sintering of the nanoparticles during the deposition process. The wet chemistry based method for the controlled deposition of submonolayer platinum is advantageous in terms of processing and maximizing the use of platinum and can, in principle, be scaled up straightforwardly to an industrial level. The reactivity of the Pt(31)-Ru sample was about 150% higher than that of the industrial benchmark PtRu (1:1) alloy sample but with 3.5 times less platinum loading. Using the Pt(31)-Ru nanoparticles would lower the electrode material cost compared to using the industrial benchmark alloy nanoparticles for direct methanol fuel cell applications.

Download or read book Incorporation of Precious Metal Nanoparticles Into Various Aerogels by Different Supercritical Deposition Methods written by Carl D. Saquing and published by . This book was released on 2005 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Application of Ruthenium Nanoparticles with Determined Structure in the Catalytic Oxidation of Carbon Black and Propylene written by Rita Mahfouz and published by . This book was released on 2017 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt: The synthesis of the newly discovered fcc ruthenium nanoparticles and the conventional hcp nanoparticles was established via the chemical reduction method. The nanoparticles were supported on ceria and zirconia and then thermally stabilized by calcination at 400oC or 600oC. A series of ruthenium-based catalysts were also prepared by the dry impregnation method and further calcined. The catalysts prepared by both techniques were evaluated for their catalytic activities in the oxidation reactions of carbon black and propylene. The fcc Ru nanoparticles with PVP were successfully synthesized and their XRD results were compatible with the reference. TPR results of fcc and hcp Ru/CeO2 catalysts showed the presence of well-dispersed ruthenium oxide species which were responsible for their remarkable catalytic activities in both oxidation reactions. Fcc and hcp Ru/ZrO2 catalysts revealed minimal catalytic performance as a result of their lower oxygen storage capacity. Among the impregnated catalysts, imp Ru/CeO2-600oC recorded the highest decrease in Tm under loose contact conditions in the total combustion of carbon black.

Download or read book Preparation of Supported PT Based Mixed Nanoparticles and Their Catalytic Properties written by Kwok-Ying Tsang and published by Open Dissertation Press. This book was released on 2017-01-27 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "Preparation of Supported Pt-based Mixed Nanoparticles and Their Catalytic Properties" by Kwok-ying, Tsang, 曾幗瑛, 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 PREPARATION OF SUPPORTED PT-BASED MIXED NANOPARTICLES AND THEIR CATALYTIC PROPERTIES submitted by TSANG KWOK YING for the degree of Doctor of Philosophy at The University of Hong Kong in September 2007 Selected Pt-based mixed nanoparticles were prepared and their catalytic properties were studied. Platinum-cobalt nanoparticles were prepared from water/Triton X-100/propanol- 2/cyclohexane reverse microemulsions. The Pt: Co ratio in the nanoparticles was controlled by the initial concentrations of Pt and Co in the precursor solution. The nanoparticles were characterized by transmission electron microscopy, x-ray diffractometry and energy dispersive x-ray analysis. The Pt-Co nanoparticles supported on a carbon electrode possessed high dispersion and high catalytic activity for methanol oxidation in alkaline solution at room temperature. The optimum Pt: Co ratio for methanol oxidation was determined to be 1:0.5. A method to prepare supported nanoparticles of Pt-WO with composition control in nanoscale was developed. Transmission electron microscopy showed crystalline domains in the nanoparticles, which had a narrow size distribution. Energy dispersive x-ray analyses performed in different regions showed good uniformity in the Pt: W ratio, which correlated linearly with the Pt: W ratio in the precursor. Platinum was mostly present in the pure metallic state whereas tungsten is in the +6 oxidation state, as revealed by x-ray iphotoelectron spectroscopy. The Pt-WO nanoparticles supported on Vulcan XC 72 carbon exhibited high activity for methanol oxidation at room temperature. The electrocatalytic activity varied with the Pt: W ratio with an optimum at 1:1. At this ratio, the activity is better than a commercial PtRu/C catalyst of equivalent platinum loading. Some Pt/Ru nanoparticles supported on Vulcan-72 carbon were also prepared by the colloidal method and mixed with Bi O . The prepared Pt/Ru/Bi O nanoparticles were 2 3 2 3 characterized by EDX, TEM and XPS. Their catalytic activities towards formic acid decomposition were studied. The rate of gas generation was measured and the gaseous products were analyzed by gas chromatography. Pt/Ru/Bi O nanoparticles showed high 2 3 activity and selectivity towards the dehydrogenation of formic acid. A composition of Pt: Ru: Bi O is 3:1:3 showed the highest activity. 2 3 ii DOI: 10.5353/th_b3963418 Subjects: Nanoparticles Catalysts

Download or read book Synthesis and Characterization of Carbon Nanotube Supported Platinum and Titanium Dioxide Nanoparticles written by Qianqian Liu and published by . This book was released on 2011 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt: Platinum (Pt) supported on single-walled carbon nanotube (SWCNT) is one of the most efficient catalysts for methanol electroxidation. However, there is lack of a facile and environmental method to synthesize Pt nanoparticles on SWCNT. In the first section, I investigated a novel method to synthesize Pt nanoparticles on SWCNT using DNA molecules as dispersing agent for nanotube uniformly suspended in aqueous solutions and templates for the synthesis of Pt nanoparticles. The morphology of DNA molecules and Pt nanoparticles and their distributions along SWCNT were studied with the use of a number of electron microscopy and microanalysis techniques; electrocatalytic activities of Pt nanoparticles for methanol oxidations were characterized using cyclic voltammetry and A.C. impedance spectroscopy; and interactions among SWCNT, DNA molecules, and Pt nanoparticles were characterized by UV-visible spectroscopy. As a result, I found DNA molecules affect the synthesis of Pt nanoparticles around SWCNT and electrocatalytic activity of Pt nanoparticles supported on SWCNT for methanol oxidations. In the second section, I investigated two approaches for synthesizing carbon nanotube (CNT) coated with TiO2 nanoparticles for solar cell applications. One method used titanium sulfate (Ti (SO4)2) as a reaction precursor, and a second method employed titanium isopropoxide (Ti (OCH (CH3)2)4) as a reaction precursor. My experimental results indicate that without surface functionalization of CNT, nanotube coated with sensitizing TiO2 nanoparticles could be obtained through the selection of desirable precursors and reaction parameters-using Ti (OCH (CH3)2)4 as a reaction precursor.

Download or read book Synthesis and Characterisation of Iron Platinum Nanoparticles written by and published by . This book was released on 2007 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Preparation of Supported Pt based Mixed Nanoparticles and Their Catalytic Properties written by Kwok-ying Tsang and published by . This book was released on 2007 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Platinum Nanoparticles Prepared in Water in oil Microemulsions written by and published by . This book was released on 2001 with total page 32 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 Synthesis Characterization and Deposition of Platinum Nanoparticles written by Dulan B. Gunasekara and published by . This book was released on 2009 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Sustainable Preparation of Metal Nanoparticles written by Rafael Luque and published by Royal Society of Chemistry. This book was released on 2013 with total page 243 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Synthesis of Shape controlled Platinum Nanoparticles written by Changmingzi Xu and published by . This book was released on 2012 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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.