Tip-To-Middle Anisotropic MOF-On-MOF Growth with a Structural Adjustment

Abstract

Well-organized construction of hybrid metal−organic frameworks (MOFs) with complicated structures or components is a great importance because of their potential usefulness. In this regard, the conjugation of more than two MOFs, which have dissimilar components and/or structures, is a smart strategy for the production of hybrid MOFs. MOF-on-MOF growth is fundamental for the conjugation of two MOFs and should be deeply understood for the finely controlled conjugation and for the formation of well-organized hybrid MOFs. Herein, we report an interesting MOF growth process for the construction of hybrid MOF particles containing heterogeneous components and cell lattices. Interestingly, even though a newly grown MOF and an MOF template have mismatched cell lattices, the anisotropic growth results in unexpectedly well-defined core−shell-type hybrid MOFs. Comprehensive monitoring of the growth process revealed a tip-to-middle MOF-on-MOF growth, which elucidates the uncommon formation of a well-defined core−shell hybrid despite the anisotropic growth. A tip-to-middle anisotropic growth process is accompanied by self-adjustment of MOF cell lattices to anchor on the template surface having mismatched cell lattices in the early reaction stage and self-reversion of cell lattices to the original comfortable configuration in the middle stage of the reaction.

Ternary MOF-on-MOF heterostructures with controllable architectural and compositional complexity via multiple selective assembly

“…A ternary MOF-on-MOF film by sequential epitaxial growth of three different Cu-based MOFs on Cu(OH) 2 modified foil is demonstrated by Takashi and co-workers 42 . Very recently, a double shelled core-shell Fe-MIL-88B@Ga-MIL-88B@Fe-MIL-88C ternary MOF-on-MOF heterostructure with similar compositions is reported by Oh and colleagues 43 . To our knowledge, there is no report on the synthesis of ternary MOF-on-MOF materials with controllable architectural and compositional complexity.…”

“…It is noted that the growth of guest MOF on one specific facet of host MOF has been reported to generate binary MOF-on-MOF structures 28 , 37 – 39 , 43 , 46 . However, utilizing one host MOF with different facets that can individually regulate the growth of other guest MOF building blocks is demonstrated in this work.…”

In-plane Assembly of Distinctive 2D MOFs with Optimum Supercapacitive Performance

“…Synthesizing core-shell MOF structure is one popular means to merge multiple functions of different 3D MOFs together to one unit for optimizing utilization (Lee et al, 2020;Zhang et al, 2018 performance for hybrid supercapacitors. Herein based on our previous work using Co(OH) 2 as both the precursor and the template, we have successfully integrated two-layered MOFs into one homogeneous, oriented 2D MOF array, which shows further substantial electrochemical performance promotion (Deng et al, 2018).…”

Rational Design and Growth of MOF‐on‐MOF Heterostructures

“…In 2020, Lee et al. [ 105 ] reported a tip‐to‐middle growth covering process to synthesize a type of core‐shell MIL‐88B@MIL‐88C hybrid by an anisotropic growth. At the beginning, they utilized Fe‐MIL‐88B (Hexagonal, a = b = 10.72 Å, c = 19.17 Å) as a MOF seed to guide the formation of Fe‐MIL‐88C (Hexagonal, a = b = 10.18 Å, c = 23.77 Å) with similar structures as well as topologies but two dicarboxylic acids with different length, namely, H 2 BDC and H 2 NDC = 2,6‐naphthalenedicarboxylic acid in Figure 1c.…”