Morphological and Microstructural Stability

Since CVD-based techniques are free of carbonaceous particles they allow the direct growth of CNTs on substrates. In the work of K.B.K. Teo et ah, carbon nanotube growth was performed by adding acetylene to the NH3 gas flow (at a ratio of typically 20%) for 15 min [62]. If exactly the same catalyst and growth conditions are used in the presence of a plasma discharge (i.e., PECVD), vertically 

Communications, 8(9), Tsai MC, Yeh TK, and Tsai CH, An improved electrodeposition technique for preparing platinum and platinum-ruthenium nanoparticles on carbon nanotubes directly grown on carbon cloth for methanol oxidation, 1445-52, 32006, with permission from Elsevier.) 

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Third, diamond films deposited on nondiamond substrates could possess significant internal stress, both intrinsic and thermal [16]. The role that stress plays, macroscopically and microscopically, in the electrochemical response is not understood at present. One possible manifestation of localized stress could be less morphological and microstructural stability during exposure to harsh electrochemical conditions. 

Morphological and microstructural stability over a wide potential range Rapid electron-transfer kinetics for a wide range of redox systems Easily fabricated, shaped, and inexpensive in cost... 

In a recent communication [91], Ni surface alloyed with Cu, Ti, or Cu + Ti by ion implantation was examined for its redox and electrocatalytic activities by cyclic voltammetry. The surface was characterized by XPS, x-ray, and electron diffraction, as well as by electron and atomic force microscopies. This type of material exhibited a unique voltammetric response of Ni and was shown to stabilize the / -modification of the Ni oxide/hydroxide. It was demonstrated that the morphology and microstructure differ from those of bulk materials. 

The properties of acid-bearing polymers are determined by (a) the chemical nature of the monomers (b) the microstructure of the polymer (c) their molecular weight and molecular weight distribution and (d) their morphology in the solid state. Sulfonated polymers usually exhibit a much higher proton conductivity than phosphonylated or carboxylated polymers for a given ion content, and generally aromatic polymers exhibit better chemical and thermal stability than aliphatic polymers. Moreover, physicochemical... 

Electrodes consisting of supported metal catalysts are used in electrosynthesis and electrochemical energy conversion devices (e.g., fuel cells). Nanometer-sized metal catalyst particles are typically impregnated into the porous structure of an sp -bonded carbon-support material. Typical carbon supports include chemically or physically activated carbon, carbon black, and graphitized carbons [186]. The primary role of the support is to provide a high surface area over which small metallic particles can be dispersed and stabilized. The porous support should also allow facile mass transport of reactants and products to and from the active sites [187]. Several properties of the support are critical porosity, pore size distribution, crush strength, surface chemistry, and microstructural and morphological stability [186]. 

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