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Shape control of multi-material hete...

University of California, Berkeley.

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Shape control of multi-material heterostructures for catalytic applications.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Shape control of multi-material heterostructures for catalytic applications./
Author:	Habas, Susan Ellen.
Description:	129 p.
Notes:	Adviser: Peidong Yang.
Contained By:	Dissertation Abstracts International69-10B.
Subject:	Chemistry, Inorganic. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3334305
ISBN:	9780549874607

Shape control of multi-material heterostructures for catalytic applications.
Habas, Susan Ellen.

Shape control of multi-material heterostructures for catalytic applications. - 129 p.

Adviser: Peidong Yang.

Thesis (Ph.D.)--University of California, Berkeley, 2008.

Shape control of nanomaterials has become increasingly important, as many of their physical and chemical properties are highly dependent on morphology. A tremendous amount of effort has been spent in attempt to control these properties through manipulation of size, composition, and shape. Nanocrystal shape control for both single- and multiple-material systems, however, remains largely empirical and still presents a major challenge. In this dissertation, new methods are described for the rational synthetic design of heterostructures with controlled morphology which is essential for tailoring the catalytic properties of these multi-material systems.

ISBN: 9780549874607Subjects--Topical Terms:

517253
Chemistry, Inorganic.

Shape control of multi-material heterostructures for catalytic applications.
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020 $a 9780549874607
035 $a (UMI)AAI3334305
035 $a AAI3334305
040 $a UMI $c UMI
100 1 $a Habas, Susan Ellen. $3 1043200
245 1 0 $a Shape control of multi-material heterostructures for catalytic applications.
300 $a 129 p.
500 $a Adviser: Peidong Yang.
500 $a Source: Dissertation Abstracts International, Volume: 69-10, Section: B, page: .
502 $a Thesis (Ph.D.)--University of California, Berkeley, 2008.
520 $a Shape control of nanomaterials has become increasingly important, as many of their physical and chemical properties are highly dependent on morphology. A tremendous amount of effort has been spent in attempt to control these properties through manipulation of size, composition, and shape. Nanocrystal shape control for both single- and multiple-material systems, however, remains largely empirical and still presents a major challenge. In this dissertation, new methods are described for the rational synthetic design of heterostructures with controlled morphology which is essential for tailoring the catalytic properties of these multi-material systems.
520 $a Catalytic activity and selectivity are governed by the nature of the catalyst surface, making shaped nanocrystals ideal substrates for understanding the influence of surface structure on heterogeneous catalysis at the nanoscale. First, synthetic methods were developed to produce catalytically active platinum nanocrystals with control over their shape and surface chemistry. Initially, the focus was on the removal of strongly-bound surface stabilizing molecules by ligand exchange to give catalytically clean surfaces. However, the presence of foreign ions used as a shape control agent to produce cubic, cuboctahedral, and octahedrally shaped nanocrystals was found to inhibit catalytic activity. In response, a method was developed for the shape control of uniform platinum nanoparticles stabilized by weakly interacting alkylammonium ions in the absence of foreign metal ions, which showed improved activity for ethylene hydrogenation.
520 $a The next section describes the application of these highly-faceted platinum nanocrystals as nucleation centers for overgrowth of a secondary metal to obtain shape-controlled heterostructures. Seeded growth allows for the use of the surface structure and corresponding chemical identity of a well-defined seed to control nucleation and growth of another material. Cubic platinum seeds can direct the epitaxial overgrowth of palladium to give shape-controlled core-shell type nanocrystals with structure-sensitive catalytic properties. Incorporation of a lattice-mismatched metal such as gold, on the other hand, introduces an element of selectivity leading to the growth of anisotropic binary nanocrystals where both metals are exposed.
520 $a The development of multi-component nanoparticles represents a new approach for creating smart materials, requiring controlled and selective growth of different materials on a single particle. In the final section, the concept of seeded overgrowth has been extended to include semiconductor nanostructures as seeds, introducing even greater potential for selective overgrowth of metals due to the unique chemical composition of the different crystallographic facets. Platinum and related binary metals were grown with high selectivity on the tips of cadmium sulfide nanorods for catalytic and energy applications.
590 $a School code: 0028.
650 4 $a Chemistry, Inorganic. $3 517253
650 4 $a Engineering, Materials Science. $3 1017759
690 $a 0488
690 $a 0794
710 2 0 $a University of California, Berkeley. $3 687832
773 0 $t Dissertation Abstracts International $g 69-10B.
790 $a 0028
790 1 0 $a Yang, Peidong, $e advisor
791 $a Ph.D.
792 $a 2008
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3334305