Application of Ru and Other Catalysts

This section describes in detail three topics in heterogeneous catalysis to which DFT calculations have recently been applied with great effect, the prediction of CO oxidation rates over RuO2(110), the prediction of ammonia synthesis rates by supported nanoparticles of Ru, and the DFT-based design of new selective catalysts for ethylene epoxidation. All three examples involve the careful application of DFT calculations and other appropriate theoretical methods to make quantitative predictions about the performance of heterogeneous catalysts under realistic operating conditions. 

In this chapter that highlights the synthesis of arylamines, we will discuss the most recent and relevant developments in the catalytic arylations of imine substrates, which incidentally are mostly enantioselective. The application of organomet2Jlic cat2dysts bearing Pd, Rh, Ru, and other metal catalysts will be considered, as well as the recent multicomponent Petasis reaction. 

According to survey data from ammonia plants, compared with other catalysts, the industrial application of the wiistite-based catalyst reduces the reduction time, decreases the operation temperature and pressure, increases the net ammonia concentration and production capacity, reduce the energy consumption. Compared with the Ru/C catalyst, the wiistite-based catalyst has the advantages of cheap raw material, low cost of production and comparative high activity at low temperatures. Thus, it is promising for Further development and application. 

In the following chapter examples of XPS investigations of practical electrode materials will be presented. Most of these examples originate from research on advanced solid polymer electrolyte cells performed in the author s laboratory concerning the performance of Ru/Ir mixed oxide anode and cathode catalysts for 02 and H2 evolution. In addition the application of XPS investigations in other important fields of electrochemistry like metal underpotential deposition on Pt and oxide formation on noble metals will be discussed. 

This reaction is quite different from the other P-H addition reactions in that it involves external nucleophilic attack of HPPh2 on the vinylidene ligand as shown in Scheme 13. The ZIE ratio depends on the structures of the substrate and the catalyst. Ru-Cp" (Cp =77 -CsMes) species selectively forms the Z isomer while Ru-Cp (Cp r -CsHs) favors the E isomer. Since the key intermediate is the vinylidene species that has an electrophilic carbon, the reaction is applicable to other alkynes that are vinylidene precursors. Thus, phenylacetylene also reacts similarly to give Ph2PCH=CHPh ZIE=93I7), while internal alkynes are totally unreactive. 

Water-soluble transition metal complexes, which are effective catalysts in other hydrogenation processes, were found to be effective catalysts in C02 hydrogenation. The first report disclosed the application of Rh complexes with water-soluble phosphine ligands in water-amine mixtures to afford formic acid.122 Water-soluble Ru-phosphine121,123,124 and Rh-phosphine123 124 complexes were used in aqueous solution to hydrogenate C02 or HCO3 to formic acid or HCOO-, respectively. 

Reddington et al. (66) reported the synthesis and screening of a 645-member discrete materials library L9 as a source of catalysts for the anode catalysis of direct methanol fuel cells (DMFCs), with the relevant goal of improving their properties as fuel cells for vehicles and other applications. The anode oxidation in DMFCs is reported in equation 1 (Fig. 11.12). At the time of the publication, state-of-the-art anode catalysts were either binary Pt-Ru alloys (67) or ternary Pt-Ru-Os alloys (68). A systematic exploration of ternary or higher order alloys as anode catalysts for DMFCs was not available, and predictive models to orient the efforts were also lacking. 

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