Interface, catalytic

The first report of surface-immobilized dendrimers was in 1994 [54]. Subsequently, our research group showed that the amine-terminated PAMAM and PPl dendrimers could be attached to an activated mercaptoimdecanoic acid (MUA) self-assembled monolayer (SAM) via covalent amide linkages [55, 56]. Others developed alternative surface immobilization strategies involving metal com-plexation [10] and electrostatic binding [57]. These surface-confined dendrimer monolayers and multilayers have found use as chemical sensors, stationary phases in chromatography, and catalytic interfaces [41,56,58,59]. Additional applications for surface-confined dendrimers are inevitable, and are dependent only on the synthesis of new materials and the development of clever, new immobilization strategies. 

In order that a reactant in the main fluid phase may be converted catalytically to a product in the main fluid phase, it is necessary that the reactant be transferred from its position in the fluid to the catalytic interface. be activatedly adsorbed on the surface, and undergo reaction to form the adsorbed product. The product must then be desorbed and transferred from the interface to a position in the fluid phase. The rate at which each of these steps occurs influences the distribution of concentrations in the system and plays a part in determining the over-all rate. Because of the differences in the mechanisms involved, it is convenient to classify these steps as follows when dealing with catalysts in the form of porous particles ... 

The activated adsorption of reactants and the activated desorption of products at the catalytic interface. 

Steps 1 and 2 of the above scheme are physical steps, to be treated in later chapters. Steps 3 and 4 are chemical and will be treated here. To do so. we consider the fluid state to be given at a point alongside the catalytic interface, where 7 . is to be calculated. With this specification, a direct analog of the previous example is the conversion of a gaseous reactant A to a gaseous product P on the catalyst surface according to the following reaction scheme ... 

In the first case, YSZ electrolyte of thickness 250 - 400 microns is covered with Ni-cermet anode and LSM cathode of thickness 25-50 microns. IPPE has 4 patents for technology of porous catalytic interfaces electrode-solid electrolyte . More than 200 single cells of this type were tested. At 950 C, power density of 700 mW/cm was achieved (Fig. 6). 

The problem we would like to address is schematically shown in Figure 17.1 A catalytic interface (inset) is surrounded by a proton-carrier hydrated membrane the reactants, intermediates, and products diffuse in and out to reach or leave the catalyst surface, and the substrate is the electronic conductor material which may also influence the reactive system given the nanoscale of the actual... 

The aforementioned photo-oxidation of sulfur aniones can eventually lead to disruption of the ZnS crystals and release of Zn2+ ions that could not be completely prevented even by efficient hole scavengers [271]. In the context of primordial photochemistry, such a photocorrosion would have led to the continuous rejuvenation of the ZnS surfaces and the formation of fresh (photo)catalytic interfaces. In addition, photocorrosion would have continuously released Zn2+ ions, keeping their concentration at the illuminated ZnS surfaces high. 

Ignaszak A, Ye S, Gyenge E (2008) A study of the catalytic interface for 02 electrraeductitm on Pt the interaction between carbon support meso/microstructure and ionomer (Nation) distribution. J Phys Chem C 113(l) 298-307... 

In order to convert the reactant in bulk fluid phase into the product, it is necessary for the reactant to be transferred from its position in the fluid to the catalytic interface and adsorbed on the surface, and to undergo reaction to form the adsorbed product. The product is then desorbed and transferred from the interface to a position in the bulk fluid phase. 

The Catalytic Interface Catalyst/Support/Ionomer Interaction... 

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