Polymer-capped bimetallic nanocluste

N. Toshima, Polymer-capped bimetallic nanoclusters as active and selective catalysts, in N. Ueyama, A. Harada (eds.) Macromolecular Nanostructured Materials, Kodansha/ Springer, Tokyo/Berlin, 2004, 182. 

Polymer-capped Bimetallic Nanoclusters as Active and Selective Catalysts... 

In this section the preparation and catalytic properties of the colloidal dispersion of polymer-capped bimetallic nanoclusters will be discussed, emphasizing the importance of polymers for controlling the structure and stabilizing the dispersions of bimetallic nanoclusters in preparation processes as well as for the improvement of the activity and selectivity in catalyses. Although there are many reports on the preparation of industrial catalysts composed of bimetallic nanoclusters and inorganic supports, they are not included in this section. 

Preparation and Structure of Polymer-capped Bimetallic Nanoclusters... 

An alcohol reduction method in which alcohol like ethanol can work both as a reductant and a solvent has been applied to the synthesis of polymer-capped bimetallic nanoclusters. They have been prepared by the simultaneous reduction of the two corresponding metal ions with refluxing alcohol. For example, colloidal dispersions of Pd/Pt bimetallic nanoclusters can be prepared by refluxing... 

Polymer-capped bimetallic nanoclusters containing both light transition metal and precious metal can also be prepared by a modified alcohol reduction method. For example, Cu/Pd bimetallic nanoclusters were successfully prepared with various Cu Pd ratios by refluxing a glycol solution of the hydroxides of Cu and Pd in the presence of PVP or by the thermal decomposition of metal acetates. 

Polymer-capped bimetallic nanoclusters are very effective as catalysts. The combination of various metals can produce many kinds of bimetallic nanoclusters of various structures. We can now freely control the structure of bimetallic nanoclusters. Recently, we have succeeded in preparing triple core/shell structured trimetallic nanoclusters which have much higher catalytic activity than the corresponding bimetallic nanoclusters. Thus, the present author believes that researches on polymer-capped bi- or tri-metallic nanoclusters are progressing rapidly and that the results will be applied to various practical chemical processes in the near future. 

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