Download or read book Synthesis Characterisation and Activity of Ruthenium N doped Multi walled Carbon Nanotubes Catalysts written by Letlhogonolo Fortunate Mabena and published by . This book was released on 2013 with total page 370 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis and Characterization of Novel Carbon Nanostructures Supported Catalysts and Their Effects on Methanol and Ethanol Electro oxidation written by Raghavendar Reddy Sanganna Gari and published by . This book was released on 2009 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt: Alternative energy conversion systems are receiving great attention due to the depletion of fossil fuels and increasing environmental pollution. Due to excellent features such as high energy density, low operating temperature, and high energy conversion efficiency, direct methanol (DMFC) and ethanol fuel cells (DEFC) are promising power sources to address future energy problems. However, their performance is limited by low electrocatalytic activity of anodes for methanol and ethanol oxidations, and the high cost of noble metal platinum (Pt) based catalysts. One approach to enhance catalytic activity and to reduce the cost is to explore novel carbon materials as catalyst supports. In this work, single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs), and graphene-supported Pt and Pt-Ru catalysts were synthesized by an ethylene glycol (EG) reduction method. Comparative electrochemical measurements of different carbon structure-supported catalysts were conducted using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry techniques. Experimental results show that SWCNT-supported Pt and Pt-Ru catalysts have a higher catalytic activity and lower charge transfer resistance towards methanol and ethanol oxidation in comparison to MWCNT-supported catalysts. The electrocatalytic activities of graphene-supported catalysts were compared with commercial Vulcan XC-72 carbon black-supported catalysts and graphite supported catalysts. Experimental results suggest that graphene-supported Pt and Pt-Ru nanoparticles possess superior electrocatalytic activity than carbon black and graphite supports.

Download or read book Nitrogen Doped Carbon Nanotubes written by S. van Dommele and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis and Characterization of Carbon Nanotube Supported Nanoparticles for Catalysis written by Ganesh Vijayaraghavan and published by . This book was released on 2007 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation describes the synthesis and characterization of nitrogen doped carbon nanotube (NCNT) supported nanoparticles for catalysis, specifically, the cathodic oxygen reduction reaction (ORR) in fuel cells. Strategies for synthesis of mono- and bimetallic nanoparticle catalysts through dendrimer based templating techniques and with the aid of metal organic chemical vapor deposition (MOCVD) precursors and efficient assembly protocols of the catalysts with the NCNTs are discussed in detail. Physicochemical properties of the NCNTs and NCNT supported catalysts were characterized using a host of tools including scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, x-ray photoelectron spectroscopy (XPS), thermo gravimetric analysis, BET surface area and pore size analysis and electrochemical techniques including cyclic voltammetry, chronocoulometry, chronoamperometry and rotating disk electrode voltammetry. Chapter 1 serves as a general introduction and provides a brief overview of challenges associated with the synthesis, characterization and utilization of graphitic carbons and graphitic carbon supported catalysts in heterogeneous catalysis. Chapter 2 provides an overview of the synthesis and characterization of systematically doped iron and nickel catalyzed NCNTs in an effort to understand the effect of nitrogen doping on ORR. Chapter 3 describes the use of NCNTs as supports for dendrimer templated nanoparticle catalysts for ORR. A facile synthetic strategy for the immersion based loading of catalysts onto NCNTs by spontaneous adsorption to achieve specific catalyst loadings is explored. Chapter 4 details the loading of monodisperse Pt, Pd and PtPd catalysts on the as synthesized NCNTs using MOCVD precursors. The MOCVD route offers promise for direct dispersion and activation of ORR catalysts on NCNT supports and eliminates a host of problems associated with traditional solvent based catalyst preparation schemes. Chapter 5 details future directions on a few topics of interest including efficient electrodeposition strategies for preparing NCNT supported catalysts, studies on PtCu catalysts for ORR and finally prospects of using NCNT supported catalysts in fuel cell applications.

Download or read book CVD Synthesis of Carbon Nanostructures and Their Applications as Supports in Catalysis written by Jacques Teddy and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work, we describe the synthesis, structure, physical properties and some applications in catalysis of previously known carbon allotropes, and recently discovered carbon nanostructure (Chapter I). First, FB-OM-CVD deposition was used for metal or metal oxide deposition on metal oxide supports like alumina or silica, leading to the production of supported catalysts. The resulting material was used as catalyst for catalytic chemical vapor deposition of carbonaceous nanostructures i.e single- and multi-walled carbon nanotubes (SWCNTs, MWCNTs), carbon nanofibers (CNFs), and nitrogen doped carbon nanotubes (N-MWCNTs) and nanofibers (N-CNFs) (Chapter II). After catalyst removal by a H2SO4 or NaOH treatments and carboxylic surface group generation by a HNO3 treatment in the case of MWCNTs and CNFs, the carbon nanostructures were used as supports for heterogeneous catalysis. The hydrogenation of cinnamaldehyde was used as a model reaction to compare the performance of different bimetallic Pt-Ru catalysts as a function of the nature of the support. Detailed parametric studies as well as the effect of a heat treatment on the performance improvement of the Pt-Ru/MWCNT catalyst are presented. An explanation for the increase of performances upon heat treatment will be proposed after HREM, EDX, EXAFS and WAXS characterization of the catalyst (Chapter III). The prepared carbon nanostructures were also tested as supports for Pd based electrocatalysts for direct alkaline fuel cells applications in both cathodes for the ORR reaction and anodes for alcohols oxidation.

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 Nanostructured Carbon Materials for Catalysis written by Philippe Serp and published by Royal Society of Chemistry. This book was released on 2015-03-02 with total page 570 pages. Available in PDF, EPUB and Kindle. Book excerpt: "We heartily recommend this book to all readers who wish to gain a better understanding of nanostructured carbon materials surface properties and used in catalysis." An-Hui Lu, ChemCatChem There is great interest in using nanostructured carbon materials in catalysis, either as supports for immobilizing active species or as metal-free catalysts due to their unique structural, thermal, chemical, electronic and mechanical properties, and tailorable surface chemistry. This book looks at the structure and properties of different doped and undoped nanocarbons including graphene; fullerenes; nanodiamonds; carbon nanotubes and nanofibers; their synthesis and modification to produce catalysts. Special attention is paid to adsorption, as it impacts the application of these materials in various industrially relevant catalytic reactions discussed herein, in addition to photocatalysis and electrocatalysis. Written by leading experts in the area, this is the first book to provide a comprehensive view of the subject for the catalysis community.

Download or read book Synthesis of Nitrogen doped Carbon Nanotubes written by Kambiz Chizari and published by . This book was released on 2011 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the discovery of carbon nanotubes (CNT) in 1991, a lot of efforts have been done in order to find out their intrinsic properties and their possible applications. One of the most efficient methods used for tuning its physical and chemical properties is doping CNTs by nitrogen or boron. The aim of this work deals with the synthesis of nitrogen-doped carbon nanotubes (N-CNTs) and with the study of the catalytic performance of this material either as catalyst support or as a metal-free catalyst. The influence of the different synthesis parameters on the physical and chemical properties of the N-CNTs was investigated. Afterwards, the N-CNTs were used as catalyst support for the hydrogenation of cinnamaldehyde and its catalytic performance was compared to that obtained on the undoped CNTs. It was shown that N-CNTs synthesized in different conditions lead to different catalytic performances which was mainly linked with the nature of the incorporated nitrogen species. The N-CNTs were also employed as a metal-free catalyst for the selective oxidation of H2S into elemental sulfur and the results are discussed within this thesis. Recently 2D carbon material, namely graphene, has received a great interest due to its special physical properties. The previous investigations on the other graphitic material such as carbon nanotubes facilitate the understanding of the properties and behavior of this material. In this thesis we also worked on the synthesis of the few-layer graphene (FLG), using microwave irradiations. A preliminary study has also done on the nitrogen-doping of this material by microwave treatment on the expanded graphite dispersed in ammonium hydroxide. The FLGs were used as a catalyst support for the hydrogenation of cinnamaldehyde and its catalytic performance is compared to other graphitic materials such as natural graphite, expanded graphite and carbon nanotubes.

Download or read book Catalysis written by C Kemball and published by Royal Society of Chemistry. This book was released on 2007-10-31 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: There is an increasing challenge for chemical industry and research institutions to find cost-efficient and environmentally sound methods of converting natural resources into fuels chemicals and energy. Catalysts are essential to these processes and the Catalysis Specialist Periodical Report series serves to highlight major developments in this area. This series provides systematic and detailed reviews of topics of interest to scientists and engineers in the catalysis field. The coverage includes all major areas of heterogeneous and homogeneous catalysis and also specific applications of catalysis such as NOx control kinetics and experimental techniques such as microcalorimetry. Each chapter is compiled by recognised experts within their specialist fields and provides a summary of the current literature. This series will be of interest to all those in academia and industry who need an up-to-date critical analysis and summary of catalysis research and applications. Catalysis will be of interest to anyone working in academia and industry that needs an up-to-date critical analysis and summary of catalysis research and applications. Specialist Periodical Reports provide systematic and detailed review coverage in major areas of chemical research. Compiled by teams of leading experts in their specialist fields, this series is designed to help the chemistry community keep current with the latest developments in their field. Each volume in the series is published either annually or biennially and is a superb reference point for researchers. www.rsc.org/spr

Download or read book Nanotubes and Nanosheets written by Ying (Ian) Chen and published by CRC Press. This book was released on 2015-02-24 with total page 630 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reveals Innovative Research on BN Nanotubes and NanosheetsNanotubes and Nanosheets: Functionalization and Applications of Boron Nitride and Other Nanomaterials is the first book devoted to nanotubes and nanosheets made of boron nitride (BN). It shows how the properties of BN nanotubes and nanosheets have led to many exciting applications where carb

Download or read book Synthesis and Characterization of Nitrogen Boron Chlorine and Fluorine Doped Carbon Nanotubes written by Adeniyi Olugbenga Osikoya and published by . This book was released on 2013 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon nanotubes (CNTs) doped with nitrogen, boron, chlorine and fluorine have been synthesized in a catalytic chemical vapour deposition (CCVD) reactor at 700 and 800 °C, using cobalt and silver as catalysts supported on magnesium oxide. The synthesized carbon nanotubes were characterized by Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Raman spectroscopy, X-ray diffraction spectroscopy (XRD), Thermogravimetric analysis (TGA) and Energy dispersive spectroscopy (EDS). Carbon nanotubes doped with nitrogen were found to have internal bamboo shaped structures in the TEM results. Carbon nanotubes doped with boron were also found to have compartmentalized internal structures with narrower inner diameter compared to the outer diameter. SEM characterization shows that carbon nanotubes doped with chlorine have tapered or spike-like external morphology. While fluorine doped carbon nanotubes shows the formation of a lot of carbon nanospheres and, amorphous carbon in addition to the formation of tubular structures with rough and grainy-like external morphology.

Download or read book Fischer Tropsch Synthesis on Functionalized Carbon Nanotubes written by Sewa Pokhrel and published by . This book was released on 2014 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt: The aim of this research was to investigate the role of chemical functionalization on carbon nanotubes surfaces and its effect on FT catalysis. Multi walled carbon nanotubes (MWNT) were first treated with acid (HCl) to remove the residual metal particles and were then functionalized using H 2 O2 and HNO3 to introduce oxygen-containing groups to the MWNT surface. These treatments also add defects on MWNT surface. Morphological analyses were performed on the MWNT samples with TEM and it was found that the peroxide and acid treated MWNTs showed an increase oxygen functional groups and created additional surface defects on the MWNTs. Results of FT experiments showed enhanced CO conversion, FT activity and product selectivity towards liquid hydrocarbons due to functionalization. The liquid selectivity was found to be significantly high for H2 O 2 treated catalyst. HNO3 treated catalyst had highest activity although selectivity to methane and CO2 was found higher than the H2 O2 treated catalyst. It was observed that the chemical treatments increase the carbon chain length of the produced hydrocarbons. While comparing hydrocarbon distribution of as-produced and H2 O2 treated MWNT, it was found that carbon-chain length increases for peroxide treated catalyst. Along with as-produced and functionalized nanotube, FT experiments were also conducted using B-doped sponge, un-doped sponge and N-doped CNT catalyst. B-doped sponge showed enhanced CO conversion and FT activity as compared to un-doped sponge. Conversion and product selectivity were found to be affected by temperature when test was conducted with N-CNT. Operating conditions like temperature, syngas feed flow rate and syngas ratio were also to impact the FT performance.

Download or read book Nitrogen doped Carbon Nanotubes written by Lucy Mudiwo Ombaka and published by . This book was released on 2015 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Carbon Nanotubes and Graphene written by Kazuyoshi Tanaka and published by Newnes. This book was released on 2014-07-10 with total page 458 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon Nanotubes and Graphene is a timely second edition of the original Science and Technology of Carbon Nanotubes. Updated to include expanded coverage of the preparation, purification, structural characterization, and common application areas of single- and multi-walled CNT structures, this work compares, contrasts, and, where appropriate, unitizes CNT to graphene. This much expanded second edition reference supports knowledge discovery, production of impactful carbon research, encourages transition between research fields, and aids the formation of emergent applications. New chapters encompass recent developments in the theoretical treatments of electronic and vibrational structures, and magnetic, optical, and electrical solid-state properties, providing a vital base to research. Current and potential applications of both materials, including the prospect for large-scale synthesis of graphene, biological structures, and flexible electronics, are also critically discussed. - Updated discussion of properties, structure, and morphology of biological and flexible electronic applications aids fundamental knowledge discovery - Innovative parallel focus on nanotubes and graphene enables you to learn from the successes and failures of, respectively, mature and emergent partner research disciplines - High-quality figures and tables on physical and mathematical applications expertly summarize key information – essential if you need quick, critically relevant data

Download or read book Synthesis and Characterization of Cobalt manganese based Bulk Catalysts Applied for the Growth of Multi walled Carbon Nanotubes written by Michael Jakob Bernhard Becker and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Carbon Nanotubes written by Mohammad Naraghi and published by BoD – Books on Demand. This book was released on 2011-08-09 with total page 620 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon Nanotubes are among the strongest, toughest, and most stiff materials found on earth. Moreover, they have remarkable electrical and thermal properties, which make them suitable for many applications including nanocomposites, electronics, and chemical detection devices. This book is the effort of many scientists and researchers all over the world to bring an anthology of recent developments in the field of nanotechnology and more specifically CNTs. In this book you will find: - Recent developments in the growth of CNTs- Methods to modify the surfaces of CNTs and decorate their surfaces for specific applications- Applications of CNTs in biocomposites such as in orthopedic bone cement- Application of CNTs as chemical sensors- CNTs for fuelcells- Health related issues when using CNTs

Download or read book Doped Multi walled Carbon Nanotubes written by Bindu Sadanadan and published by . This book was released on 2003 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: