Catalysts nanostructured

Figure 19 illustrates key steps of the FI2O2 formation at the nanostructured catalyst surface. An important feature is the imprintment and maintenance of the (11 0) crystal surface through the polymer template because the specific row of metal atoms favours the formation of hydrogen peroxide while minimizing byproducts such as water. 

CFPs are (disappointingly underscored) ideal supports for the preparation of supported M° nanostructured catalysts to be employed under liquid phase conditions. 

Figure 12. The relationship between the logarithm of the relative hydrogenation rate over CFP-supported rhodium nanoclusters, with respect to the polymer-stabilized nanostructured catalyst, for a number of a number of alkenes, as a function of their affinity to the support (expressed as the square difference of the solubility parameter of the support and of the substrate). (Reprinted from Ref [33], 1991, with permission from the American Chemical Society.)...

Metal Vapor-Derived Nanostructured Catalysts in Fine Chemistry The Role Played by Particle Size in the Catalytic Activity and Selectivity... 

BB-SFG, we have investigated CO adsorption on smooth polycrystaHine and singlecrystal electrodes that could be considered model surfaces to those apphed in fuel cell research and development. Representative data are shown in Fig. 12.16 the Pt nanoparticles were about 7 nm of Pt black, and were immobilized on a smooth Au disk. The electrolyte was CO-saturated 0.1 M H2SO4, and the potential was scanned from 0.19 V up to 0.64 V at 1 mV/s. The BB-SFG spectra (Fig. 12.16a) at about 2085 cm at 0.19 V correspond to atop CO [Arenz et al., 2005], with a Stark tuning slope of about 24 cm / V (Fig. 12.16b). Note that the Stark slope is lower than that obtained with Pt(l 11) (Fig. 12.9), for reasons to be further investigated. The shoulder near 2120 cm is associated with CO adsorbed on the Au sites [Bhzanac et al., 2004], and the broad background (seen clearly at 0.64 V) is from nomesonant SFG. The data shown in Figs. 12.4, 12.1 la, and 12.16 represent a hnk between smooth and nanostructure catalyst surfaces, and will be of use in our further studies of fuel cell catalysts in the BB-SFG IR perspective. 

Suslick KS, Hyeon T, Fang M, Cichowlas AA (1995) Sonochemical synthesis of nanostructured catalysts. Mater Sci Eng, A 204(1-2)486-192... 

Bruce C. Gates, Supported Nanostructured Catalysts Metal Complexes and Metal Clusters Ralph T. Yang, Nanostructured Absorbents... 

Various works has pointed out the role of the nanostructure of the catalysts in their design.18-26 There is a general agreement that the nanostructure of the oxide particles is a key to control the reactivity and selectivity. Several papers have discussed the features and properties of nanostructured catalysts and oxides,27-41 but often the concept of nanostructure is not clearly defined. A heterogeneous catalyst should be optimized on a multiscale level, e.g. from the molecular level to the nano, micro- and meso-scale level.42 Therefore, not only the active site itself (molecular level) is relevant, but also the environment around the active site which orients or assist the coordination of the reactants, may induce sterical constrains on the transition state, and affect the short-range transport effects (nano-scale level).42 The catalytic surface process is in series with the transport of the reactants and the back-diffusion of the products which should be concerted with the catalytic transformation. Heat... 

Suslick, K.S., Hyeon, T., Fang, M., and Cichowlas, A., Sonochemical preparation of nanostructured catalysts, in Advanced Catalysts and Nanostructured Materials, Moser, W., Ed., Academic Press, San Diego, 1996, p. 197, chap. 8. 

The kinetics of selective CO oxidation over the Cu Cej r02, nanostructured catalysts can be well described by employing Mars and van Krevelen type of kinetic equation derived on the basis of a redox mechanism ... 

Unsteady-state oxidation experiments were carried out by employing the step change in CO concentration over the preoxidized catalyst [62], Figure 7.14 represents the CO and C02 responses after a step change from He to 1 vol% CO/He over the fully oxidized Cu0 j Ce0 902 > nanostructured catalyst. At low temperatures, CO breakthrough is delayed for a few seconds as can be seen from Figure 7.14a. At a temperature of 250°C, however, 20 sec is needed for the first traces of CO exit... 

Step Change Experiments for the Oxidation of CO Over Completely Oxidized Cu01Ce09O2 y Nanostructured Catalyst in the Absence of Oxygen in the Reactor Feed... 

An efficient, low temperature oxidation catalyst was developed based on highly disperse metal catalyst on nanostructured Ti02 support. Addition of dopants inhibits metal sintering and prevents catalyst deactivation. The nanostructured catalyst was formulated to tolerate common poisons found in environments such as halogen- and sulfur-containing compounds. The nanocatalyst is capable of oxidizing carbon monoxide and common VOCs to carbon dioxide and water at near ambient temperatures (25-50 °C). 

The design employs filters for particulate removal, a single desiccant wheel coated with both low temperature VOCs oxidation catalyst based on nanostructured catalyst and regenerable VOCs adsorbent made from modified mesoporous silica. The distribution of the active elements along the wheel thickness was optimized and shown in Fig. 12.8-6. The adsorbents are coated along two-thirds of the wheel thickness and all catalysts are concentrated on one... 

The electrocatalytic activity of the nanostructured catalysts was investigated for electrocatalytic reduction of oxygen and oxidation of methanol. Several selected examples are discussed in this section. The results from electrochemical characterization of the oxygen reduction reaction (ORR) are first described. This description is followed by discussion of the results from electrochemical characterization of the methanol oxidation reaction (MOR). 

NANOPOROUS AND NANOSTRUCTURED CATALYSTS Self-Assembly AND Co-Assembly of Multiple Site-Isolated Catalytic Sites on Mesoporous Materials... 

New Synthetic Methods to Efficient Nanoporous and Nanostructured Catalysts 85... 

---