Silver Cluster Formation, Dynamics, and Chemistry in Metal−Organic Frameworks

详细信息    查看全文

• 作者：Ronald J. T. Houk ; Benjamin W. Jacobs ; Farid El Gabaly ; Noel N. Chang ; A. Alec Talin ; Dennis D. Graham ; Stephen D. House ; Ian M. Robertson ; Mark D. Allendorf
• 刊名：Nano Letters
• 出版年：2009
• 出版时间：October 14, 2009
• 年：2009
• 卷：9
• 期：10
• 页码：3413-3418
• 全文大小：262K
• 年卷期：v.9,no.10(October 14, 2009)
• ISSN：1530-6992

文摘

Synthetic methods used to produce metal nanoparticles typically lead to a distribution of particle sizes. In addition, creation of the smallest clusters, with sizes of a few to tens of atoms, remains very challenging. Nanoporous metal−organic frameworks (MOFs) are a promising solution to these problems, since their long-range crystalline order creates completely uniform pore sizes with the potential for both steric and chemical stabilization. We report a systematic investigation of silver nanocluster formation within MOFs using three representative MOF templates. The as-synthesized clusters are spectroscopically consistent with dimensions ≤1 nm, with a significant fraction existing as Ag₃ clusters, as shown by electron paramagnetic resonance. Importantly, we show conclusively that very rapid TEM-induced MOF degradation leads to agglomeration and stable, easily imaged particles, explaining prior reports of particles larger than MOF pores. These results solve an important riddle concerning MOF-based templates and suggest that heterostructures composed of highly uniform arrays of nanoparticles within MOFs are feasible.