In the global search for renewable sources of energy, hydrogen is a promising candidate in transportation and electronic applications. Carbon nanotubes (CNTs) have the largest hydrogen storage capacity among the hydrogen storage materials known at present. The Ni-MH battery can be used to store and then discharge large amounts of hydrogen reversibly by using hydrogen storage materials as negative electrode. The electrochemical hydrogen storage performances of metal hydride electrodes with different levels of multi wall carbon nanotubes (20%, 15%, 10%, 5% and 2% of Ni-MH battery's active materials) has been investigated under similar charge-discharge conditions. Electrochemical test cell consisted of a single hydrogen storage negative electrode sandwiched between two NiOOH/Ni(OH)2 positive electrodes. A 6M aqueous KOH solution was used as electrolyte. Electrochemical properties such as specific discharge capacity, high rate charge-discharge capability and cycle life stability have been investigated. The morphology and structure of negative electrode material were examined by scanning electron microscopy, transmission electron microscopy and X-ray diffraction analysis. Chemical analysis of the hydrogen storage alloy was performed using electron probe microanalysis, electron diffraction spectroscopy and induced coupled plasma spectroscopy analysis. Hydrogen absorption-desorption properties were measured in terms of pressure-composition-isotherm curves. It has been found in this study that the presences of CNTs significantly enhanced the overall electrochemical properties of the Ni-MH battery. Maximum specific discharge capacity was observed for 5% CNTs electrode reaching 243 mAh/g, whereas 0% CNTs could only reach 229 mAh/g. High rate charge and discharge capabilities of 5% CNTs electrodes were ~ 241% and 250% higher than the corresponding values for 0% CNTs electrode. Furthermore, the differences in electrochemical hydrogen storage of CNTs with different diameters of 10-20 nm, 20-40 nm, 40-60 nm, and 60-100 nm were investigated. Electrochemical results demonstrated that CNTs with different diameters showed a large variation in the electrochemical hydrogen storage capability under the similar experimental condition. A comparison between electrodes with different CNTs studies was carried out in order to optimize nanotubes choices for Ni-MH battery. It was found that smaller tube diameters, 20-40 nm and 5% CNTs negative electrode showed the best electrochemical properties of Ni-MH battery system.

Thesis (M.Sc.(Chemistry))--University of Pretoria, 2001. / Summaries in Afrikaans and English.

Conducting diamond electrodes provide unique advantages for electrochemistry such as a wide potential window, low baseline current, chemical inertness and resistance to fouling. De Beers boron-doped diamond electrodes, manufactured by chemical vapour deposition and containing varying amounts of boron, were therefore investigated in order to determine their suitability for future electrochemical applications. These electrodes were initially characterised using techniques such as SEM, LA-ICP-MS, Raman spectroscopy and XPS. The electrochemical behaviour of these electrodes was investigated in two redox systems (potassium iron (III) cyanide and cerium (III) sulphate) and two biological systems (dopamine and ascorbic acid). These results were compared against that of the conventional glassy carbon electrode. Porous boron-doped diamond, a novel electrode material, was used for the electrochemical detection of thyroid hormones (L-T3 and L-T4). These hormones have never previously been investigated using a boron-doped diamond electrode. The De Beers boron-doped diamond electrode was found to outperform the conventional glassy carbon electrode, which fouled very easily, in the detection of dopamine. Peak separation between dopamine and the interfering ascorbic acid was attained at a pretreated boron-doped diamond electrode. The feasibility of detecting thyroid hormones using a porous boron-doped diamond electrode was demonstrated, and the electrode material was patented. / Dissertation (MSc (Chemistry))--University of Pretoria, 2006. / Chemistry / unrestricted

Thesis (Ph. D.)--Rutgers University, 2009. / "Graduate Program in Ceramic and Materials Science and Engineering." Includes bibliographical references.

Thesis (Ph.D)--Mechanical Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Graham, Samuel; Committee Member: Garimella, Srinivas; Committee Member: Kippelen, Bernard; Committee Member: Melkote, Shreyes; Committee Member: Ready, Jud. Part of the SMARTech Electronic Thesis and Dissertation Collection.

This dissertation explores the use of nanocarbons both as conductive supports for redox enzyme electrochemistry and as electrocatalytic components for the nonmediated detection of biogenic analytes. More specifically, the influence of nitrogen doping of these nanocarbons (referred to herein as nitrogen-doped carbon nanotubes, or N-CNTs) on their bioelectrocatalytic performance is studied through direct enzyme adsorption and exploitation of the N-CNTs' inherent reactivity toward H₂O₂ to create H₂O₂-based sensing strategies. Both nondoped CNTs and N-CNTs may be effectively incorporated into biogenic sensing assemblies, as demonstrated herein using a variety of electrochemical techniques. Chapter 1 gives a general overview of the scope of this research and describes previous studies conducted within our laboratories that demonstrate our CNTs' promise as biogenic electrode materials. Chapter 2 describes the chemical vapor deposition (CVD) method used to prepare both CNTs and N-CNTs and establishes their suitability for use in the detection schemes outlined in later chapters through long-term stability studies. Additionally, the redox activity of Fe nanoparticles entrapped in the CNTs as a result of this CVD growth process is examined using a host of electrochemical experiments. Importantly, the data presented in this chapter show that these Fe particles do not explain the observed electrocatalytic response of the CNTs. Chapter 3 explores the direct adsorption of horseradish peroxidase (HRP) at both nondoped and N-CNTs. Spectroscopic and electrochemical assays are used to compare the extent of HRP enzymatic activity upon immobilization at both types of CNTs. Both types of HRP/CNT composites are then utilized in a quantitative H₂O₂ sensing strategy. Chapter 4 discusses the intrinsic reactivity of N-CNTs toward H₂O₂. Koutecky-Levich plots are used to demonstrate differences in H₂O₂ consumption mechanisms between NCNTs and traditional peroxidases. By replacing HRP with N-CNTs in an amperometric glucose detection scheme, the versatility of N-CNTs as a peroxidase substitute for biogenic analyte detection is demonstrated. Chapter 5 outlines future directions for this research, including possible strategies for improving electron transfer between HRP and both types of CNTs. This chapter also presents a newly developed, mediated oxidase-substrate electrochemical detection method that can easily be modified to incorporate CNTs.

No description available.

Typescript. / Thesis (PhD)--Macquarie University (Division of Environmental & Life Sciences, Dept. of Chemistry & Biomolecular Sciences), 2005. / Includes bibliographical references. / Microelectrode voltammetry -- Experimental -- Microelectrode fabrication -- Characterisation of the carbon film surface: Surface stability - X-ray photoelectron spectroscopy - Raman spectroscopy - Capacitance - Edge plane concentration - Potential window - Surface concentration of alkenes and alkynes - Outer sphere electron transfer using hexaamineruthenium (III) chloride - Reduction of potassium hexacyanoferrate (III) - Anodic oxidation: diol to dione; dopamine and ascorbic acid - Surface oxidation - Ferrocene in a non aqueous solvent -- Selectivity: Formation of carboxylic acid groups on a carbon film surface by ferrous II sulfate complex oxidation - Ethanol modified carbon film surface - Modification of carbon film microelectrode surface using aromatic amines - Modification of carbon film surfaces to form a dual functional ascorbic acid barrier -- In vivo anti fouling properties of surface modified carbon film microelectrodes -- Conclusion. / In this thesis a procedure is presented for the fabrication of a microelectrode to monitor the neurotransmitter dopamine in vivo. The microelectrodes are fabricated by in situ pyrolysis of acetylene under a nitrogen blanket onto a quartz capillary. The carbon film was then anodically oxidised in the presence of 2,4-dinitroaniline. These microelectrodes are stable, provide the physical strength to penetrate brain tissue, have a low capacitance, are resistant to fouling in vivo and selectively suppress the endogenous ascorbic acid which oxidises at the same potential as dopamine. With such properties the carbon film microelectrode appears ideally suited for fast scanning cyclic voltammetric studies of cationic neurotransmitters such as dopamine in vivo. / xxviii, 323 p. ill

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

Thesis (Ph.D.)--University of Melbourne, School of Chemistry, 2006. / Typescript. Includes bibliographical references.