Chemistry

Coated Catalysts

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Science  13 Jan 2006:
Vol. 311, Issue 5758, pp. 149
DOI: 10.1126/science.311.5758.149b

One cause of deactivation in heterogeneous catalysts is that the metallic nanoparticles can aggregate over time, leading not only to a loss of active surface but also to less favorable electronic or support interactions that depend on particle size. Jiang and Gao have explored the use of hyperbranched polymers for encapsulating palladium nanoparticles in the context of supported catalysts, in this case by functionalizing the channels in mesoporous silica SBA-15 with polyamidoamine dendrimers. The selectivity of hydrogen-ation of allyl alcohol to 1-propanol increased for generations three and four of the dendrimer versus generations one and two, and the formation of acetone was about a factor of 4 lower for the generation-three catalyst versus Pd supported on alumina. The catalysts retained their activity after several rounds of reuse or after storage for 1 month under ambient conditions. — PDS

J. Am. Chem. Soc. 10.1021/ja056424g (2005).

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