Atomistic Insights into the Oriented Attachment of Tunnel-Based Oxide Nanostructures

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• 作者：Yifei Yuan ; Stephen M. Wood ; Kun He ; Wentao Yao ; David Tompsett ; Jun Lu ; Anmin Nie ; M. Saiful Islam ; Reza Shahbazian-Yassar
• 刊名：ACS Nano
• 出版年：2016
• 出版时间：January 26, 2016
• 年：2016
• 卷：10
• 期：1
• 页码：539-548
• 全文大小：727K
• ISSN：1936-086X

文摘

Controlled synthesis of nanomaterials is one of the grand challenges facing materials scientists. In particular, how tunnel-based nanomaterials aggregate during synthesis while maintaining their well-aligned tunneled structure is not fully understood. Here, we describe the atomistic mechanism of oriented attachment (OA) during solution synthesis of tunneled α-MnO₂ nanowires based on a combination of in situ liquid cell transmission electron microscopy (TEM), aberration-corrected scanning TEM with subangstrom spatial resolution, and first-principles calculations. It is found that primary tunnels (1 × 1 and 2 × 2) attach along their common {110} lateral surfaces to form interfaces corresponding to 2 × 3 tunnels that facilitate their short-range ordering. The OA growth of α-MnO₂ nanowires is driven by the stability gained from elimination of {110} surfaces and saturation of Mn atoms at {110}-edges. During this process, extra [MnO_x] radicals in solution link the two adjacent {110} surfaces and bond with the unsaturated Mn atoms from both surface edges to produce stable nanowire interfaces. Our results provide insights into the controlled synthesis and design of nanomaterials in which tunneled structures can be tailored for use in catalysis, ion exchange, and energy storage applications.