Download or read book Block Copolymer Templated Bimetallic Nanoparticles for Fuel Cell Applications written by Kyle Mikkelsen and published by . This book was released on 2014 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Block Copolymers in Nanoscience written by Massimo Lazzari and published by Wiley-VCH. This book was released on 2007-06-27 with total page 447 pages. Available in PDF, EPUB and Kindle. Book excerpt: This first book to take a detailed look at one of the key focal points where nanotechnology and polymers meet provides both an introductory view for beginners as well as in-depth knowledge for specialists in the various research areas involved. It investigates all types of application for block copolymers: as tools for fabricating other nanomaterials, as structural components in hybrid materials and nanocomposites, and as functional materials. The multidisciplinary approach covers all stages from chemical synthesis and characterization, presenting applications from physics and chemistry to biology and medicine, such as micro- and nanolithography, membranes, optical labeling, drug delivery, as well as sensory and analytical uses.

Download or read book Block Copolymer Templated Extended Surface Precious Metal Nanostructures as Model Electrocatalysts written by Deepra Bhattacharya and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development and commercialization of efficient electrochemical energy conversion devices such as electrolyzers and fuel cells is crucial to the realization of a carbon-neutral economy based on hydrogen. Electrochemical reactions underlying the operation of such devices are catalytic in nature, and because they operate under extreme electric potentials and pH, the choice of catalyst materials is limited to highly stable elements platinum and other platinum group metals (PGMs). The cost and scarcity of PGMs is, hence, a major bottleneck to the economic proliferation of fuel cells and electrolyzers. Electrocatalytic reaction systems, being constrained by the concurrence of electron and ion transport phases in addition to chemical species transport at the catalyst surface, are highly dependent on spatial synergy between an electrocatalyst material and its surroundings, and to this end, considerable research has been performed in the past decade on the nanostructuring and morphology control of electrocatalyst layers. However, the lack of suitable modes of fabrication that allow for the control of electrocatalyst nanostructure over experimentally relevant length scales (several millimeters) has limited systematic analyses of the dependence of electrocatalyst feature sizes and morphologies on their performance. This dissertation reports the development and subsequent testing of nanostructured PGM electrocatalysts of tunable feature size and morphology that can be fabricated with few or no defects over experimentally significant areas. The nanostructures, templated from the self-assembly of block copolymers, have been developed via liquid- and gas- phase fabrication pathways, as both free-standing and supported moieties of lamellar and cylindrical morphologies with features ranging from 11 nm -- 35 nm. A combination of electron microscopy, atomic force microscopy, X-ray scattering, diffraction, and photoelectron spectroscopy have been used to obtain near-perfect pattern transfer of the block copolymer nanopatterns onto Platinum and Iridium oxide nanostructures on Si wafer and Glassy Carbon substrates. Testing for electrocatalytic performance for hydrogen evolution/oxidation and oxygen reduction has been carried out on interdigitated microelectrode arrays as two-point measurements as well as on a conventional three-electrode setup in 0.1 M perchloric acid with ultra-low PGM loadings (~5.8 [mu]gPt cm-2). Catalyst performance probed as a function of nanoscale feature size and morphology reveals an inverse correlation between particle size and electroactivity, as well as the superiority of cylindrical morphologies over lamellae. Moreover, the results demonstrate electrocatalyst performance that rivals commercial platinum electrocatalysts in terms of mass activity (380 mA mgPt-1 at 0.9 V vs RHE), whilst surpassing commercial catalysts in terms of stability (mass activity loss: 11.45% at after 20,000 potential cycles). Overall, the dissertation presents BCP templating as a fabrication pathway towards stable, tunable nanostructured geometries for probing electrocatalyst functional response on model surfaces.

Download or read book Electrocatalysis in Fuel Cells written by Minhua Shao and published by MDPI. This book was released on 2018-09-28 with total page 689 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a printed edition of the Special Issue "Electrocatalysis in Fuel Cells" that was published in 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 584 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

Download or read book Block Copolymer Nanocomposites written by Galder Kortaberria and published by CRC Press. This book was released on 2016-10-14 with total page 339 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive overview of the synthesis and characterization of nanocomposites based on block copolymers. Because of the self-assembly capability of block copolymers for the generation of nanostructures, besides their ability to nanostructure thermosetting matrices such as epoxy and polyester, binary or ternary nanocomposites can be prepared with different nanofillers such as nanoparticles and carbon nanotubes. The book starts with a review on nanocomposites based on block copolymers and nanoparticles synthesized with the use of surfactants, followed by a review on nanocomposites with metallic nanoparticles with polymer brushes and those with carbon nanotubes. A chapter is devoted to binary systems based on block copolymers and nanoparticles synthesized by sol-gel. A review on nanocomposites based on thermosetting matrices nanostructured with block copolymers (amphiphilic or chemically modified) is also presented for both epoxy and polyester resins. The work on ternary systems based on thermosetting matrices, block copolymers, and nanoparticles is presented next. The book concludes with a discussion on nanocomposites based on epoxy and block copolymers with azobenzene groups for optical purposes.

Download or read book Block Copolymer Templated Nitrogen enriched Nanocarbons written by Mingjiang Zhong and published by . This book was released on 2013 with total page 315 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Reversible-deactivation radical polymerization (RDRP), also referred to as controlled/"living" radical polymerization (CRP) has been developed over the past 20 years. RDRP promotes the synthesis of well-defined polymeric materials with controlled molecular weights and molecular weight distributions, complex topologies and functionalities. In the past decade, the Matyjaszewski and Kowalewski groups pioneered the work of synthesizing nanostructured carbon by pyrolysis of polyacrylonitrile (PAN) containing polymeric precursors prepared via RDRP. My contribution to this topic was primarily focused on the following aspects: (1) optimization of the synthetic procedure, (2) deeper investigation of the structures, (3) exploration of the surface chemistry with particular emphasis of nitrogen functionality, (4) and energy related applications. This thesis first focuses on addressing current challenges in RDRP particularly in atom transfer radical polymerization (ATRP), one of the most robust RDRP techniques. Based on the development of a deep mechanistic understanding of RDRP's, ATRP was then used for the synthesis of PAN containing block copolymers followed by applying a series of analytical tools to provide detailed physical characterization. Finally, these materials were utilized as precursors for the formation of nanocarbons that were evaluated in various energy related applications. The development of nanostructured carbon materials from PAN precursors is discussed in Chapter 1. Particular emphasis is placed on the rational structural design of PAN containing polymeric precursors developed in the Matyjaszewski and Kowalewski groups, while the detailed synthetic methodology will be discussed in the subsequent chapters. Controlled synthesis is the prerequisite for many applications. The successful preparation of block copolymers via RDRP requires preparation of a macroinitiator with preserved chain end functionality (CEF). Work described in Chapter 2 resulted in the establishment of a universal rule for quantifying the CEF in all RDRPs, which is also the most important criterion for determining the "livingness" and degree of control over the polymerization. The parameters affecting the level of CEF preservation are determined. Another challenge in ATRP is diminishing the concentration of catalyst employed during the polymerization procedure in order to reduce the cost and simplify the purification steps. Chapter 3 describes the systematic study of RDRP in the presence of zerovalent copper, which offers significant advantages in this regard. The contribution of all of the potential reactions occurring in an ATRP carried out in the presence of copper zero were evaluated, and a supplemental activator and reducing agent (SARA) ATRP mechanism is concluded to precisely describe this system. How to conduct and optimize SARA ATRP system is then demonstrated. Chapter 4 is focused on another aspect of the robust capability of ATRP : controlling the molecular weight distribution. Activator regeneration electron transfer (ARGET) ATRP was employed to prepare polystyrene-block-poly(methyl acrylate) copolymers with tunable dispersity in the range of 1.32 to 2.0 for each block. Knowledge attained from the studies discussed in Chapter 2 to 4 has been extensively utilized in the studies of nanocarbons. Chapter 5 discusses the preparation of a series of PAN containing diblock copolymers that were used as precursors for the preparation of nanocarbons. The block copolymers undergo phase separation and then the poly(n-butyl acrylate) serves as a sacrificial segment upon pyrolysis. Both thin film and bulk nanocarbons with diverse morphologies, resembling the original phase-separated copolymer precursors, were prepared. The carbonization of bulk copolymer precursors with branched PAN domains was of particular interest; which resulted in the formation of porous nanocarbons with large surface area and highly accessible nitrogen functionality originating from PAN. Chapter 6 illustrates how porosity and accessible nitrogen functionality in the nanocarbon introduced in Chapter 5 can be utilized for CO2 capture. The main emphasis was placed on the surface area and nitrogen content's influence on adsorption capacity and selectivity was studied. Chapter 7 discusses the application of PAN-derived nanocarbons as electrode materials for supercapacitors. Materials displaying both high energy density and high power density were achieved. This excellent performance was partially due to the mesoporous structure with high specific surface area, in combination with the pseudocapacitance originating from graphitic edge nitrogens. Evidence of electrochemical activity of the nitrogen heteroatoms provided the motivation to explore the performance of copolymer templated nanocarbon as an electrocatalyst for oxygen reduction, as described in Chapter 8. A desirable 4-electron transfer process with a low overpotential system was achieved by as-prepared nanocarbon film with porous morphology; which again, demonstrates one of the unique properties of nanocarbons prepared from PAN containing block copolymer precursors. Finally, a summary is provided in Chapter 9 and some future directions regarding synthesis and utility of heteroatom-enriched nanocarbons are discussed."--Pages ii-v.

Download or read book Nanomaterials for Fuel Cell Catalysis written by Kenneth I. Ozoemena and published by Springer. This book was released on 2016-07-05 with total page 583 pages. Available in PDF, EPUB and Kindle. Book excerpt: Global experts provide an authoritative source of information on the use of electrochemical fuel cells, and in particular discuss the use of nanomaterials to enhance the performance of existing energy systems. The book covers the state of the art in the design, preparation, and engineering of nanoscale functional materials as effective catalysts for fuel cell chemistry, highlights recent progress in electrocatalysis at both fuel cell anode and cathode, and details perspectives and challenges in future research.

Download or read book Synthesis Characterization and Application of Block Copolymer and Nanoparticle Composites written by Yue Gai and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The "bottom-up" fabrication of functional hybrid material can be achieved by using directed self-assembly of functional nanoparticles (NP) and block copolymers (BCP) as templates. The versatile nanostructures of BCP provide possibilities to precisely control NPs spatial distribution and the resulting hybrid materials exhibit enhanced electrical, mechanical and optical functionalities. Three main topics related to BCP/NP composites are discussed in this dissertation: I) the spatial distribution of large NP in linear BCP; II) the morphology control of BCP templates with new architectures; and III) the magneto-optical properties of hybrid material using magnetic NPs. For well-ordered BCP/NP composite, the ratio of NP core diameter (dcore) and BCP domain width (L) has been generally limited with dcore/L 0.3 when BCP/NP interactions are relatively neutral or weak. By modifying the Au NPs with hydrogen bonding (H-bonding) donor group, the selective spatial distribution of Au NPs ranges in size up to 0.8 times that of the target domain width in symmetric polystyrene-block-poly (2-vinylpyridine) (PS-b-P2VP). In addition, H-bonding meditated 15 nm NPs can be directed by linear BCP of dsubcore/sub/L up to 0.4 at 20wt % loading. The H-bonding interactions between NP and BCP provide favorable enthalpic interaction to overcome the inherent entropy penalties mainly arising from polymer chain stretching upon the sequestration of large particles. On the other hand, the extensive chain entanglements of linear BCP still remain a challenge for hybrid materials with the consequence of long processing duration, many defects and lack of orientation. Bottlebrush BCPs (BBCPs) exhibit much lower degree of chain entanglement due to the highly extended confirmation. A systematic study was conducted to investigate the morphology transitions that occur in polystyrene-block-poly (ethylene oxide) (PS-b-PEO) BBCPs upon varying PEO volume fraction (fsubPEO/sub) from 22 % to 81 %. Either symmetric or asymmetric lamellar morphologies were observed in the BBCPs over an exceptionally wide range of fsubPEO/sub from 28 % to 72 %. A microphase transition temperature TsubMST/sub was observed over a temperature range of 150-180 °C. Finally, enhanced magneto-optical (MO) composites with excellent Faraday rotation (FR) response were fabricated using iron platinum (FePt) NPs and PS-b-P2VP linear BCP. Gallic acid (GA) functionalized FePt NPs with average dsubcore/sub from 1.9 to 9.3 nm were selectively incorporated into a P2VP domain through H-bonding interactions. The use of copolymer template to selectively arrange the magnetic NPs enabled high MO performance with limited trade-off of scattering loss, providing a simple strategy to prepare functional materials for MO applications. Verdet constants of a 10 wt % loaded 4.9 nm FePt NP composite reached absolute magnitudes as high as ~ -6x10sup4

Download or read book Block Copolymer Templated Nitrogen enriched Nanocarbons written by Zhong Mingjiang and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Block Copolymer templated Iron Oxide Nanoparticles for Bimodal Growth of Multi walled Carbon Nanotubes written by Kyle E. Yazzie and published by . This book was released on 2008 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: (Cont.) The anionic PAA carboxylic acid groups can be used to sequester metal cations, so that metal is effectively loaded into the micelles. The size of nanoparticles can be controlled by the size of the PAA portion of the block copolymer. When spin cast onto a substrate, the metal-loaded PS-b-PAA micelles form a quasi-ordered block copolymer thin film. Maximizing the amount of metal-loaded micelles in solution can maximize the resulting areal density of nanoparticles, thereby forming a monodisperse, quasi-hexagonal nanoparticle array. The deposited micellular thin film and substrate can then be etched with oxygen plasma, removing the organic polymer so that only the nanoparticle array is left, and the substrate is ready for carbon nanotube growth.

Download or read book Advanced Electrocatalysts for Low Temperature Fuel Cells written by Francisco Javier Rodríguez-Varela and published by Springer. This book was released on 2018-10-09 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces the reader to the state of the art in nanostructured anode and cathode electrocatalysts for low-temperature acid and alkaline fuel cells. It explores the electrocatalysis of anode (oxidation of organic molecules) and cathode (oxygen reduction) reactions. It also offers insights into metal-carbon interactions, correlating them with the catalytic activity of the electrochemical reactions. The book explores the electrocatalytic behaviour of materials based on noble metals and their alloys, as well as metal-metal oxides and metal-free nanostructures. It also discusses the surface and structural modification of carbon supports to enhance the catalytic activity of electrocatalysts for fuel-cell reactions.

Download or read book Nanoparticle block Copolymer Self assembly written by Scott Charles Warren and published by . This book was released on 2007 with total page 394 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Poly vinylpyridine Nanostructures for Nanoparticle Synthesis and Energy related Catalysis written by Audrey K. Taylor and published by . This book was released on 2015 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nanoalloys written by Florent Calvo and published by Newnes. This book was released on 2013-03-12 with total page 433 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanoalloys: From Fundamentals to Emergent Applications presents and discusses the major topics related to nanoalloys at a time when the literature on the subject remains scarce. Particular attention is paid to experimental and theoretical aspects under the form of broad reviews covering the most recent developments. The book is organized into 11 chapters covering the most fundamental aspects of nanoalloys related to their synthesis and characterization, as well as their theoretical study. Aspects related to their thermodynamics and kinetics are covered as well. The coverage then moves to more specific topics, including optics, magnetism and catalysis, and finally to biomedical applications and the technologically relevant issue of self-assembly. With no current single reference source on the subject, the work is invaluable for researchers as the nanoscience field moves swiftly to full monetization. Encapsulates physical science of structure, properties, size, composition and ordering at nanoscale, aiding synthesis of experimentation and modelling Multi-expert and interdisciplinary perspectives on growth, synthesis and characterization of bimetallic clusters and particulates supports expansion of your current research activity into applications Synthesizes concepts and draws links between fundamental metallurgy and cutting edge nanoscience, aiding interdisciplinary research activity

Download or read book Fabrication of Periodic Arrays of Metallic Nanoparticles by Block Copolymer Templates on HfO2 Substrates written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advanced Nanomaterials for Fuel Cell Catalysts written by Yan Lin and published by . This book was released on 2006 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt: