CATALYSIS

Interior design with nanoparticles

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Science  29 Aug 2014:
Vol. 345, Issue 6200, pp. 1017
DOI: 10.1126/science.345.6200.1017-h

Catalysts made from metal nanoparticles (NPs) absorbed on oxide surfaces often are used in many industrial reactions and in automotive catalysts. These usually work best at high temperatures. High temperatures, however, promote surface diffusion and the subsequent formation of larger particles with less surface area, which become less active over time. Qiao et al. synthesized thermally stable NPs of palladium (Pd) and platinum within a hollow shell of microporous silica that allowed small molecules to enter and leave the interior. Polymer nanodots synthesized with the shell-bound metal ions formed NPs with average sizes under 2 nm and high thermal stability upon reduction and heating. The micropores also controlled catalytic product formation. Oxidative reduction of cyclohexene with trapped Pd NPs yielded almost pure benzene, versus a host of larger oxygenated rings for exposed Pd NPs.

J. Am. Chem. Soc. 10.1021/ja505903r (2014).

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