Download or read book Characterization and Modification of Substrates for Scanning Tunneling Microscopy and Spectroscopy Studies of Nitrogen doped Carbon Nanotubes written by Hari Chandana Bellam and published by . This book was released on 2005 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book STM Characterization of Functionalized Carbon Nanotubes and Graphene written by Van Dong Pham and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis we studied the interaction between organic molecules and carbon nanomaterials. Using scanning tunneling microscopy (STM) at low temperature and in ultra-high vacuum, we measured the properties of porphyrin molecules at the surface of graphene and single-walled carbon nanotubes. We first studied electron injection in graphene at defect sites (grain boundaries and nitrogen doping atoms). Using image-potential states, we evidenced the variation of local work function in doped graphene. Secondly, we investigated the properties of free-base porphyrin (H2TPP) molecules adsorbed on a Au(111) surface. We performed tip-induced tautomerization and dehydrogenation of the molecules, and revealed how these operations modify the molecular states and molecule-substrate interaction. Following these two preliminary studies, we studied the interaction of graphene with porphyrin molecules. We evidenced a weak electronic coupling between the molecules and graphene. We then showed how a nitrogen dopant on doped graphene can tune the molecule-surface interaction. The comparison between molecules adsorbed on nitrogen doping sites with those adsorbed on carbon sites clearly reveals a downshift of the energy of the molecular states at the doping sites. This downshift reveals a partial electron transfer from the nitrogen sites of graphene to the adsorbed molecules. In the last part of this thesis, we studied the properties of single-walled carbon nanotubes functionalized with a porphyrin polymer. The STM measurements revealed that the polymer is partially covering the nanotubes. Local spectroscopy indicated that the local density of states are modified at the polymer location.

Download or read book Theoretical Studies of Scanning Tunneling Microscopy and Electron Transport Through Nanostructures written by Khoonghong Khoo and published by . This book was released on 2007 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterisation of Carbon Nanotubes Using Transmission Electron Microscopy and Scanning Tunneling Microscopy written by Walter Knechtel and published by . This book was released on 1998 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Carbon Nanotubes Synthesis Characterization and Applications written by Kamal K. Kar and published by Research Publishing Service. This book was released on 2011 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Scanning Tunneling Microscopy and Field Emission Studies of Carbon Nanostructures written by Philip Godfrey Collins and published by . This book was released on 1998 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Chemical Abstracts written by and published by . This book was released on 2002 with total page 2540 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 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 Characterization and Chemical Functionalization of Nitrogen Doped Carbon Nanotubes for the Application in Gas and Bio sensors written by Yangxi Fu and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Carbon Nanotubes and Related Structures written by Peter John Frederich Harris and published by Cambridge University Press. This book was released on 2001-10-18 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a 1999 book on carbon nanotubes, one of the most exciting areas in materials chemistry.

Download or read book Scanning Tunneling Microscopy and Spectroscopy of Carbon Nanotubes Interfaced with Silicon Surfaces written by Peter Michael Albrecht and published by . This book was released on 2007 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: Single-walled carbon nanotubes (SWNTs) are high-aspect-ratio molecular wires that exhibit either metallic or semiconducting behavior depending upon their diameter and chiral angle. SWNTs support high-mobility electrical conduction, are chemically and mechanically robust, and can both emit and detect infrared light. These properties recommend SWNTs as the building blocks of a future molecular nanotechnology. In the near term, however, the integration of SWNTs with silicon-based complementary metal-oxide-semiconductor (CMOS) technology holds the greatest promise in terms of economic and manufacturing feasibility. In this thesis, the ultrahigh vacuum scanning tunneling microscope (UHV-STM) is used to examine SWNTs directly interfaced with the hydrogen-passivated Si(100) surface. An approach termed dry contact transfer (DCT) was developed for the UHV deposition of SWNTs with minimal disruption of the atomically flat Si(100)-2x1:H surface. Isolated, rather than bundled, SWNTs could be routinely located on the surface for atomically resolved imaging, tunneling current-voltage spectroscopy, lateral manipulation, and cutting with the room-temperature UHV-STM. The removal of hydrogen at the nanotube-silicon interface via UHV-STM electron-stimulated desorption resulted in structural and electronic modifications to the SWNT. The growing body of first-principles simulations of the SWNT/Si(100) system was drawn upon in the interpretation of such local perturbations. Weakly adsorbed SWNTs initially unstable in the presence of the rastered STM tip could be stabilized by depassivating the underlying H-Si(100) surface. Finally, feedback-controlled cutting of SWNTs with the UHV-STM was demonstrated as a precise and reproducible means of preparing one or more finite-sized SWNTs from an extended tube.

Download or read book Preparation and Characterization of Nitrogen Doped Carbon Nanotube Electrode Materials written by Stephen Maldonado and published by . This book was released on 2006 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation describes the preparation and characterization of nitrogen doped carbon nanotube films by a chemical vapor deposition (CVD) process. Thorough description of the preparation method is given. A variety of techniques are used to demonstrate the relationship between the physicochemical properties and electrochemical properties of nitrogen doped carbon nanotubes, shedding insight to the influence of nitrogen doping on observed electrocatalysis phenomena. Chapter 1 comprises a general overview of the presented material and scope of the work. Chapter 2 details the CVD preparation of nitrogen doped carbon nanotubes. Scanning electron microscopy, thermal gravimetric analysis, and x-ray photoelectron spectroscopy are used to demonstrate the degree of control afforded by the CVD process over the resultant properties of the prepared carbon nanotubes. The direct preparation of carbon nanotube films on a current collector is shown. Chapter 3 consists of a thorough characterization and comparison of nitrogen doped carbon nanotubes and non-doped carbon nanotubes. Transmission electron microscopy, thermal gravimetric analysis, and Raman spectroscopy demonstrate the increased disorder caused by nitrogen doping into the graphitic lattice structure of carbon nanotubes. X-ray photoelectron spectroscopy highlights the existence of multiple carbon-nitrogen surface functionalities that change in relative abundance as the nitrogen content is varied. Titration analyses indicate that nitrogen doped carbon nanotubes are basic and acquire a cationic surface charge in solutions of neutral pH. Chapter 4 presents a collection of voltammetric responses of several outer-sphere and inner-sphere redox probes. The similarities and differences between the responses at non-doped carbon nanotube electrodes and nitrogen doped carbon nanotube electrodes are noted and discussed in the context of the conclusions of the physical characterizations. A detailed mechanistic analysis of the O2 reduction process at nitrogen doped carbon nanotube electrodes is presented. Chapter 5 details continuing work with carbon nanotube materials for fundamental and applied studies.

Download or read book Scanning Tunneling Microscopy and Spectroscopy of Porphyrins and Carbon Nanotubes written by Mark Alexander Bissett and published by . This book was released on 2007 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Syntheses Optimizations and Characterizations of Sulfur doped and Nitrogen doped Carbon Nanodots for Metal Ion Detection written by Winnie Jiang and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Carbon nanodots are new inexpensive and nontoxic nanoparticles which have captured interest due to their multiple functionalities. One of their interesting properties is their fluorescence spectrum which is in contrast to that of carbon nanotubes. Blue sulfur-doped carbon nanodots (BS-CNDs or S-CNDs), blue nitrogen-doped carbon nanodots (N-CNDs), and orange sulfur-doped carbon nanodots (OS-CNDs) were synthesized and characterized through IR spectroscopy, Raman spectroscopy, NMR spectroscopy, UV-Vis spectroscopy, and Zetasizer light scattering. These syntheses’ goals were to make clear and brightly fluorescent solutions of carbon nanodots. OS-CNDs proved problematic due to sulfuric acid’s hygroscopic property which later affected S-CNDs. Isolation for characterization purposes was most difficult with S-CNDs, being in a highly acidic solution. In addition to their spectra, other methods were also used to characterize and isolate the carbon nanodots. The CNDs fluorescence spectra were the main property examined in this project, as well as Raman spectroscopy and Zetasizer light scattering. The stabilities and functionality of the blue carbon nanodots for the detection of metal salts were explored. S-CNDs gradually decreased in fluorescence intensity at room temperature and 40 °C and maintained their fluorescence at 0 °C and 4 °C for over 20 days. N-CNDs showed the same fluorescence at all temperatures over 20 days. S-CNDs' fluorescence was quenched in the presence of chloride ions of metal salts and was enhanced by a lithium salt. N-CNDs' fluorescence was quenched by a silver salt and enhanced in the presence of zinc and cadmium."--

Download or read book Scanning Tunneling Microscopy and Spectroscopy of Single walled Carbon Nanotubes Directly Interfaced with Atomically Pristine Silicon Surfaces written by Peter Michael Albrecht and published by . This book was released on 2004 with total page 146 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.