Oriented Nanocrystal Arrays of Selectable Polymorphs by Chemical Sculpture

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• 作者：Xianfeng Yang ; Chinnathambi Karthik ; Xiuyan Li ; Junxiang Fu ; Xionghui Fu ; Chaolun Liang ; N. Ravishankar ; Mingmei Wu ; Ganapathiraman Ramanath
• 刊名：Chemistry of Materials
• 出版年：2009
• 出版时间：July 28, 2009
• 年：2009
• 卷：21
• 期：14
• 页码：3197-3201
• 全文大小：852K
• 年卷期：v.21,no.14(July 28, 2009)
• ISSN：1520-5002

文摘

Growing crystals with selected structure and preferred orientations on seed substrates is crucial for a wide variety of applications. Although epitaxial or textured film growth of a polymorph whose structure resembles the seed crystal structure is well-known, growing oriented nanocrystal arrays of more than one polymorph, selectable one at a time, from the same seed has not been realized. Here, we demonstrate for the first time the exclusive growth of oriented nanocrystal arrays of two titania polymorphs from a titanate crystal by chemically activating respective polymorph-mimicking crystallographic facets in the seed. The oriented titania nanocrystal arrays exhibit significantly higher photocatalytic activity than randomly oriented polymorphs. Our approach of chemically sculpting oriented nanocrystal polymorph arrays could be adapted to other materials systems to obtain novel properties.