Electro-catalysts methods

The slurries of electro-catalysts were prepared by mixing together the catalysts and appropriate amount of 5wt % Nafion solution(Du Pont) including some kinds of dispersant[8]. The electrodes were made by spraying method with these well mixed inks. Two electrodes and Nafion 112 membrane were hot pressed with the condition of 50kgf/cm, 120°C for 3min to fabricate MEAs(Membrane Electrode Assembly). 

Pahnore GTR, Bertschy H, Bergens SH, Whitesides GM. 1998. A methanol/dioxygen biofuel cell that uses NAD -dependent dehydrogenases as catalysts Application of an electro-enzymatic method to regenerate nicotinamide adenine dinucleotide at low overpotentials. J Electroanal Chem 443 155-161. 

The experimental data presented in this paper demonstrates the potential of CuCl/HCl electrolysis for nuclear hydrogen production. The CuCl/HCl electrolysis reaction requires a cation exchange membrane in order to produce hydrogen at a current density that exceeds 0.1 A-cm-2. In order to carry out the hydrogen production reaction a platinum electro-catalyst is required. The copper(I) oxidation reaction, on the other hand, does not require a Pt catalyst. This reaction proceeds quite readily on Pt-free graphite electrodes. Methods to mitigate the passage of the copper ion species across the membrane need to be developed to maintain the performance of the cell at the desired level. 

Determination of Reaction Mechanisms Occurring at Fuel Cell Electro catalysts Using Electrochemical Methods, Spectroelectrochemical Measurements and Analytical Techniques... 

H. Takenaka, E. Torikai, Y. Kawami, N. Wakabayashi and T. Sakai, Studies on solid polymer electrolyte water electrolysis II. Preparation methods for membrane-electro-catalyst composite, Denki Kagaku (J. Electrochem. Soc. Jpn.), 1985, 53, 261. 

The surface area, pore volume, and pore size distributions of supports and catalysts were determined using a Micromeritics ASAP 2000 unit. Scanning electron microscopy (Zeiss DSM 940) was used for characterization of the whiskers-covered surface and washcoated samples. The thicknesses of the washcoats on flat samples were determined by an electro-magnetic method (Fischer Deltascope MP 3). The alkali content of the prepared supports was... 

CO is easily oxidized on platinum, and the recovery of CO-poisoned anodes has been discussed in detail elsewhere (Gottesfeld, 1992). The CO may also be removed by fuel starvation methods discussed in the patent literature. Development of CO-tolerant electro catalysts is also an active area of research (Huang et al., 2007). Operation of FCs at >120°C also improves their CO tolerance. 

Electro-catalyst type/substiate or support Preparation method Stmctural characteristics Noble metal loading (mg cm ) Test protocol Performance Ref. 

Mesoporous carbon materials were prepared using ordered silica templates. The Pt catalysts supported on mesoporous carbons were prepared by an impregnation method for use in the methanol electro-oxidation. The Pt/MC catalysts retained highly dispersed Pt particles on the supports. In the methanol electro-oxidation, the Pt/MC catalysts exhibited better catalytic performance than the Pt/Vulcan catalyst. The enhanced catalytic performance of Pt/MC catalysts resulted from large active metal surface areas. The catalytic performance was in the following order Pt/CMK-1 > Pt/CMK-3 > Pt/Vulcan. It was also revealed that CMK-1 with 3-dimensional pore structure was more favorable for metal dispersion than CMK-3 with 2-dimensional pore arrangement. It is eoncluded that the metal dispersion was a critical factor determining the catalytic performance in the methanol electro-oxidation. 

It should be mentioned that the structure of carbon supports could have significant influence on the electro-catalytic properties of the nanocomposite catalysts. Recently, Pt/Ru nanoclusters prepared by the alkaline EG method were impregnated into a synthesized carbon support with highly ordered mesoporous. Although the Pt/ Ru nanoclusters can be well dispersed in the pores of this carbon substrate, the long and narrow channels in this material seem not suitable for the application in... 

The study of the molecular weight of the intermediate course is an effective method for the classification of polymerization as chain or stepwise reaction. In Figure 3, the molecular weight of the obtained polymer is plotted against the yield, for the oxidative polymerization of dimethylphenol with the copper catalyst and for the electro-oxidative polymerization. The molecular weight rises sharply in the last stage of the reaction for the copper-catalyzed polymerization. This behavior is explained by a stepwise growth mechanism. 

Electro-resistively heated Pt-Ti02 or Fe203 catalysts supported on Hastelloy C-276 have been successfully used for the decomposition of S03. The Pt-TiOz catalyst has been shown to be active over a wider range of temperatures compared to the Fe203 catalyst. The combination of these two catalysts with electro-resistive heating may offer a novel method for S03 decomposition in the S-I process. 

One of the main motivations for the development of chemically modified electrodes is the introduction of (electro-) catalytic species onto the electrode surface. These modified electrodes can be used to improve specificity and product yields in electrochemical synthesis or as the basis for a biosensor. Catalysts can be attached through (irreversible) adsorption onto a suitable substrate (7). These systems mosdy consist of an electrode covered with a monolayer of the electroactive species. In many cases this method does not lead to effective systems, due to instability of the monolayer or low loading with the catalyst. Direct modification of the electrode surface by covalent... 

Although the Bonnemann method is very interesting by allowing to vary and to control easily the composition and the nanostructure of the catalyst and is adapted to the preparation of real fuel cell electrodes, it displays also some limitations. For example, bismuth-containing colloids could not be prepared with the Bonnemann method, and even in presence of platinum salts. Moreover, the presence of bismuth hinders the reduction of platinum salts [59], However, platinum-bismuth is a good catalyst for ethylene glycol electro-oxidation in alkaline medium [59-62], Moreover, colloid of tin alone could not be obtained, and the reaction was only possible by coreduction in the presence of a platinum salt. Then, other colloidal methods should be developed keeping in mind the necessity of a similar flexibility as that of the Bonnemann method. 

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