Diamond in nanoparticle form is a promising material that can be used as a robust and chemically stable catalyst support in fuel cells. It has been studied and characterized physically and electrochemically, in its thin film and powder forms, as reported in the literature. In the present work, the electrochemical properties of undoped and boron-doped diamond nanoparticle electrodes, fabricated using the ink-paste method, were investigated. Methanol oxidation experiments were carried out in both half-cell and full fuel cell modes. Platinum and ruthenium nanoparticles were chemically deposited on undoped and boron doped diamond nanoparticles through the use of NaBH(4) as reducing agent and sodium dodecyl benzene sulfonate (SDBS) as a surfactant. Before and after the reduction process, samples were characterized by electron microscopy and spectroscopic techniques. The ink-paste method was also used to prepare the membrane electrode assembly with Pt and Pt-Ru modified undoped and boron-doped diamond nanoparticle catalytic systems, to perform the electrochemical experiments in a direct methanol fuel cell system. The results obtained demonstrate that diamond supported catalyst nanomaterials are promising for methanol fuel cells.

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Dimensionally stable, high surface area support for a possible direct methanol fuel cell application was fabricated from commercial diamond nanoparticles through electrophoretic deposition onto silicon wafer substrates, and their electrochemical characteristics were examined by employing inorganic redox probes such as ͓Fe͑CN͒ 6 ͔ 3−/4− and ͓Ru͑NH 3 ͒ 6 ͔ 3+/2+ . As-received diamond nanoparticles were purified by refluxing in an aqueous nitric acid solution, and the product was characterized by using X-ray diffraction, X-ray photoelectron spectroscopy, prompt gamma-ray neutron activation analysis, Raman spectroscopy, electron energy loss spectroscopy, and transmission electron microscopy techniques. Electrophoretically deposited diamond nanoparticle layers of uniform thickness were obtained by controlling experimental parameters, such as applied voltage, deposition time, and the concentration of diamond nanoparticles in the suspension. Platinum nanoparticles were electrodeposited onto these diamond nanoparticle layers ͑Pt/DNP͒ by step and sweep potential method. Their structural and morphological characterizations were made by using scanning electron microscopy and energy-dispersive X-ray analysis. The electrochemical activity of Pt/DNP toward methanol oxidation was studied. The present study paves a way to fabricate ultrathin, uniform, high surface area, and dimensionally stable diamond electrodes in a controllable fashion. This type of deposited diamond nanoparticle layers may be considered as catalyst support material for fuel cell applications. © 2010 The Electrochemical Society. ͓DOI: 10.1149/1.3374403͔ All rights reserved. Fuel cells attract tremendous attention in the present days as environmentally sustainable systems.1 Especially, direct methanol fuel cells are developed for transportation and portable power supply applications. In spite of the numerous demonstration systems, the commercialization is hampered due to the prohibitively high costs and durability of materials. Regarding cost reduction, the noble-metal loadings must drop to a level of Ͻ1.0 mg cm −2 from the present 2.0-8.0 mg cm −2 , depending on the applications. Loading reduction through increasing platinum utilization is one of the approaches. Non-noble catalyst development is another approach. Designing high performance electrodes would be yet another approach. Dispersing catalysts on electrically conducting, high surface area carbon materials is a significant step forward to achieve a finer dispersion of the metal catalyst and to get a high electrochemically active surface area.

Nitrogen-doped graphene (N-doped Graphene; includes N-Gr and N-rGO), emerges as an interesting alternative for the development of new anodic materials for the next generation of lithium-ion batteries (LIBs). Due to their characteristics, they can be used both as active materials and in combination with other materials for the formation of composites. As a consequence of the N-Gr synthesis methodology, the physicochemical and structural properties are variable, depending on the number of layers, nitrogen percentage and configuration in the doping product, the presence of oxygenated functional groups, the electroactive area, and the 2D structure or 3D of the material, among others. These properties are closely related to its electrochemical performance, affecting the number of active sites for lithiation, lithium diffusion rate, and pathways through a battery system, charge transfer resistance, pseudo-capacitive contribution, mechanical stability, among others. In this review, we comprehensively analyze the different characteristics of N-Gr-based materials and their relationship with their performance as anodes in LIBs.