Encapsulation and Ostwald Ripening of Au and Au–Cl Complex Nanostructures in Silica Shells

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  • We are grateful to the National Science Foundation grants DMR 0404278 for supporting this study. Facilities available through the Cornell Center for Materials Research (CCMR), a Materials Research Science and Engineering Center of the National Science Foundation (DMR-0079992) were used for this study. Supporting Information is available online from Wiley InterScience or from the author.

Abstract

We report a general template strategy for rational fabrication of a new class of nanostructured materials consisting of multicore shell particles. Our approach is demonstrated by encapsulating Au or Pt nanoparticles in silica shells. Other superstructures of these hollow shells, like dimers, trimers, and tetramers can also be formed by nanoparticle-mediated self-assembly. We have also used the as-prepared multicore Au–silica hollow particles to perform the first studies of Ostwald ripening in confined microspace, in which chloride was found to be an efficient mediating ligand. After treatment with aqua regia, Au–Cl complex is formed inside the shell, and is found to be very active under in situ transmission electron microscopy observations while confined in a microcell. This aspect of the work is expected to motivate further in situ studies of confined crystal growth.

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