3 years ago

Kinetic-Controlled Formation of Bimetallic Metal–Organic Framework Hybrid Structures

Kinetic-Controlled Formation of Bimetallic Metal–Organic Framework Hybrid Structures
Zibin Liang, Wenhan Guo, Chong Qu, Ruqiang Zou, Bin Qiu, Wei Xia, Yingxiao Wu, Kunting Cai
Heterometallic metal–organic frameworks (MOFs) are constructed from two or more kinds of metal ions, while still remaining their original topologies. Due to distinct reaction kinetics during MOF formation, partial distribution of different metals within a single MOF crystal can lead to sophisticated heterogeneous nanostructures. Here, this study reports an investigation of reaction kinetics for different metal ions in a bimetallic MOF system, the ZIF-8/67 (M(2-mIM)2, M = Zn for ZIF-8, and Co for ZIF-67, 2-mIM = 2-methylimidazole), by in situ optical method. Distinct kinetics of the two metals forming single-component MOFs are revealed, and when both Co and Zn ions are present in the starting solution, homogeneous distributions of the two metals are only achieved at high Co/Zn ratio, while at low Co/Zn ratio concentration gradient from Co-rich cores to Zn-rich shells is observed. Further, by adding the two metals in sequence, more sophisticated structures are achieved. Specifically, when Co2+ is added first, ZIF-67@ZIF-8/67 core–shell nanocrystals are achieved with tunable core/shell thickness ratio depending on the time intervals; while when Zn2+ is added first, only agglomerates of irregular shape form due to the weak nucleation ability of Zn2+. Metal–organic framework (MOF) hybrids: Bimetallic MOF hybrids are synthesized in a well-designed manner based on kinetic studies monitored by in situ optical turbidity methods. Distinct growth behaviors of two isostructural monometallic MOFs are first revealed. Bimetallic MOFs with either solid-solution or core–shell nanostructure are further constructed in a kinetic-directed manner, while kinetic-blocked nanostructures are not acquired.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/smll.201702049

You might also like
Never Miss Important Research

Researcher is an app designed by academics, for academics. Create a personalised feed in two minutes.
Choose from over 15,000 academics journals covering ten research areas then let Researcher deliver you papers tailored to your interests each day.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.