Carbon nanotubes (CNTs) and nanofilaments (CNFs) were synthesized by the decomposition of ethylene using oxidized diamond-supported catalysts at a relatively mild temperature. Oxidized diamond is proposed as a novel support material for the catalytic synthesis of CNTs and CNFs. We focused on the inner structure of the CNTs which were synthesized using Ni, Co, Fe, Ni-Fe, Co-Fe, and Ni-Co-loaded oxidized diamond catalysts. The oxidation state of loaded metals in bimetallic catalysts played an important role in producing a more uniform internal structure of the synthesized CNTs. CNFs synthesized over bimetal-loaded oxidized diamond catalysts had different internal structures and fiber axis/graphene layer angles.

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Carboxylated multi-walled carbon nanotubes (MWCNTs-COOH) were attached to amino-functionalized glass by evaporation of water from an aqueous MWCNT-COOH dispersion. After attachment, MWCNTs-COOH did not detach from the glass despite physical treatments such as sonication and scrubbing with paper. Other combinations without the carboxyl and/or amino groups did not result in a firm attachment; the attachment of MWCNTs-COOH to the glass surface was achieved solely through ionic interaction (-COO^- ... ⁺H₃N-). Transmittance and electrical resistance measurements suggested that MWCNTs-COOH were bundled through attractive interaction with the MWCNTs-COOH bound to the surface.

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A brief review on materials coming after graphene (beyond graphene) is presented mainly by focusing on their preparation: hydrogenated and fluorinated graphene, oxidized graphene, graphyne and graphdiyne, boron nitride, silicene, transition metal dichalcogenides and composite nanosheets. Common strategy for the formation of these materials is to produce 2-dimensional structure composing from single to few layers.

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The fuel cell electric vehicle (FCEV) is expected to be one of the promising “ZERO” emission vehicles along with the battery electric vehicle. For the commercialization of the FCEV, it is significantly important to reduce the production cost, especially of the catalyst layer. Generally, the catalyst layer is composed mainly of Pt nano-particles and a carbon support, and their structure greatly affects the performance and durability of the fuel cell. For example, a Pt/C catalyst consisting of highly dispersed Pt nanoparticles loaded on a high-surface area carbon support is preferable to achieve a better initial performance, whereas such a catalyst often suffers from poor durability. In order to construct a well-balanced catalyst layer, the design of the carbon support is of essential importance. This review describes the mechanism of carbon corrosion caused by the drive modes of the vehicle in both cathode and anode catalyst layers, together with methods for analysis and characterization. Since these processes are often a bottleneck in the development of the FCEV, we hope that the present review will be helpful to the development and improvement of the technology related to FCEVs.

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Graphene oxide (GO) has many functions, because it has many kinds of functional groups and defects. However, a detailed analysis of the functions and the relationships between the functions and functional groups, has never been made. Here, a detailed analysis of these functions and relationships is given based on our results. The epoxide of GO is unique, and shows a reversible reaction with changing pH. The high proton conductivity of GO is attributed to the presence of epoxide in the interlayers of GO. New types of electrochemical devices such as fuel cells and lead acid batteries where GO is used as a solid proton electrolyte, are proposed. CH defects are also important for the electrode with a high capacitance in supercapacitor and magnetism. GO is also very useful as electrocatalyst substrates because there are both hydrophilic and hydrophobic nano-level areas on the surface.

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The easy synthesis of transition metal nanoparticles supported on three types of carbon nanofibers (platelet: CNF-P, tubular: CNF-T, herringbone: CNF-H) and nitrogen-doped CNF-H (N-CNF-H) is accomplished by pyrolysis of metal carbonyl clusters such as Ru₃(CO)₁₂, Rh₄(CO)₁₂, and Ir₄(CO)₁₂, and alkene complexes such as Pd₂(dba)₃·CHCl₃ and Pt(dba)₂ [dba: dibenzylideneacetone]. Transmission electron microscopy of these CNFs with immobilized metal nanoparticles (M/CNFs and M/N-CNF-H) showed that metal nanoparticles whose size could be controlled, existed on the CNFs, and that their location was dependent on the surface nanostructure of the CNFs: on the edge of the graphite layers (CNF-P), in the tubes and on the surface (CNF-T), and between the layers and on the edge (CNF-H). Among these M/CNFs, Ru/CNF-P and Rh/CNF-T showed excellent catalytic activity towards arene hydrogenation with high reusability and functional group tolerance, while the Pt/CNF-P behaves as an efficient catalyst for the hydrogenation of substituted nitroarenes to the corresponding aniline derivatives with the other functional groups remaining intact. Pt and Pd nanoparticles supported on N-CNF-H act as poisoning catalysts for the transformation of internal alkynes to (Z)-alkenes over Pd/N-CNF-H, and for the transformation of nitroarenes to the corresponding anilines and N-hydroxylamines over Pt/N-CNF-H.

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We are focusing on the effects of a porous carbonaceous material as a catalyst support for polymer electrolyte fuel cells (PEFCs). One of the important functions of support is to provide pore structures for gas diffusion into the catalyst layer of PEFCs. The aggregate structure of Ketjenblack (KB) introduces an effective pore structure into the catalyst layer, and provides high performance. By inserting the pore structure into the catalyst layer, even activated carbons without a dendritic structure should have as good a performance as do KB catalysts. Another important feature of the carbon support is the micropores and mesopores inside it. MCND (Mesoporous Carbon Nano-Dendrites) which have a highly-developed dendritic structure and large mesopore volume, shows excellent performance as a catalyst support, especially in the high current region.

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In this thesis, an attempt is made to develop techniques which allow accurate quantitative analyses of the trace amounts of carbon edge sites in graphites and other carbons which were heat-treated at as high a temperature as over 1200 ºC. On the basis of the quantitative analyses, the actual picture of the carbon structure is drawn and compared with the structural information obtained from X-ray diffractometry (XRD) and transmission electron microscopy (TEM). By using non-graphitizable and graphitizable carbons respectively prepared from poly(furfuryl alcohol) and poly(vinyl chloride), an attempt is made to determine the number of carbon edge sites by analyzing their hydrogen contents, the amounts of surface oxygen complexes and localized spins. The average sizes of carbon sheets in these carbons are estimated from the total number of edge sites. This analysis suggests that the actual size of carbon sheet in the poly(furfuryl alcohol)-derived carbons is much larger than the size detected with TEM observation. This large difference in sheet size is discussed in relation to a real structure of carbon sheets in non-graphitizable carbons. This indirect approach for understanding of carbon structure is also applied to graphitizing carbons (their heat treatment temperatures is over 2400 °C) and reveals that their actual sizes are more than 1000 times larger than those detected with XRD, and furthermore the sizes of graphite samples are essentially the same as their particle sizes. This structural information about highly developed carbons such as graphite has not been obtained so far, but only the present experimental techniques developed in this study make such analysis possible. Moreover, the developed techniques for analyzing carbon edge sites are applied not only to the high-temperature treated carbons but also to other types of carbon materials such as activated carbons and carbon blacks for understanding the practical performance of these carbon materials from a molecular point of view. This additive attempt shows that the performances are strongly influenced by the amounts and nature of carbon edge sites irrespective of the uses of the carbon materials. Therefore the amount and nature of carbon edge sites must be analyzed to understand the carbon structure, controlled to improve the performance and finally optimized to design the most suitable products.

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