Solvated metal atom dispersed catalysts

Solvated Metal Atom Dispersed (SMAD) Bimetallic Catalysts... 

In order to discriminate between the activity of the different gold species on ceria, our group prepared ceria-supported gold catalysts by classical deposition-precipitation (DP) followed by drying at 393 K, and by the solvated metal atom dispersion (SMAD) technique... 

Solvated metal atoms can be dispersed in excess organic solvent at low temperature and used as a source of metal particles for the preparation of both unsupported metal powders and supported metal catalysts158,161. Alternatively, metal vapor is condensed into a cold solution of a stabilizing polymer to form crystallites of the order 2-5 nm in diameters159. Equation 17 illustrates the unique activity of a colloidal Pd catalyst in the partial hydrogenation of acenaphthene. 

The dispersion of Pt(0) inside the functionalized resins was carried out by two main routes. The first is based on impregnation of the resin with a mesitylene solution of Pt nanoclusters (Solvated Pt Atoms) obtained via MVS. The second procedure, called Chemical Incorporation and Reduction (CIR), implies the immobilization of convenient molecular Pt precursors (i.e. [Pt(NH3)4]Cl2) in the pre-swollen resins, followed by chemical reduction of the metal center. Among the Pt catalysts obtained by the CIR procedure only Pt/CF3 exhibits a high conversion of the... 

Since the late 1990s, new approaches to the dispersion of noble metal particles in polymer matrixes by means of chemical, photochemical and radiation-chemical reduction, the evaporation of metal atoms (including solvated ones) into different supports, etc. have been developed (see Section 8-1) [44]. Nevertheless, catalysts prepared from individual immobilized metal clusters have more definite, mostly predetermined, structures. For these purposes derivatives of Oss, It4, RU4, Rh4, Rh6, etc. clusters are most often used. Earlier studies [46] showed that the rate of ethylene hydrogenation promoted by tetrairidium or tetraruthenium carbonyl clusters bound to phosphynated polymers decreased with an increase of the number of donor... 

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