A synthetic route to ultralight hierarchically micro/mesoporous Al(III)-carboxylate metal-organic aerogels

Abstract

Developing a synthetic methodology for the fabrication of hierarchically porous metal-organic monoliths that feature high surface area, low density and tunable porosity is imperative for mass transfer applications, including bulky molecule capture, heterogeneous catalysis and drug delivery. Here we report a versatile and facile synthetic route towards ultralight micro/mesoporous metal-organic aerogels based on the two-step gelation of metal-organic framework nanoparticles. Heating represents a key factor in the control of gelation versus crystallization of Al(III)-multicarboxylate systems. The porosity of the resulting metal-organic aerogels can be readily tuned, leading to the formation of well-ordered intraparticle micropores and aerogel-specific interparticle mesopores, thereby integrating the merits of both crystalline metal-organic frameworks and light aerogels. The hierarchical micro/mesoporosity of the Al-metal-organic aerogels is thoroughly evaluated by N2 sorption. The good accessibility of the micro/mesopores is verified by vapour/dye uptake, and their potential for utilization as effective fibre-coating absorbents is tested in solid-phase microextraction analyses.

Kinetically tuned dimensional augmentation as a versatile synthetic route towards robust metal–organic frameworks

“…Problems arise when targeting chemically stable MOFs through conventional one-pot reactions: The overall design of novel MOFs with expected structures, even simple functionalization of existing MOFs for targeted applications, becomes very challenging because of the unpredictable in situ formation of inorganic building blocks; mixed phases often come out together due to the formation of diverse inorganic building blocks; polycrystalline or even amorphous products are prone to form 17 , which not only bring challenges in structure determination, but also influence the properties of the targeted products. To address these problems, we present a general method, which is derived from the rationalization of the MOF growth process from both a kinetic and a thermodynamic perspective, of synthesizing Fe-MOF single crystals with preformed inorganic building blocks [Fe 2 M(m 3 -O)(CH 3 COO) 6 ] (M ¼ Fe 2 þ ,3 þ , Co 2 þ , Ni 2 þ , Mn 2 þ , Zn 2 þ ).…”

Mercury nano-trap for effective and efficient removal of mercury(II) from aqueous solution

“…Thiol/thio-functionalized adsorbents, including clays 10 , resins 11 , mesoporous silica [12][13][14][15][16] , activated carbons 17 , mesorporous carbons 18 and chalcogenides 19,20 , are considered very effective sorbents for Hg(II) removal from aqueous solutions due to the soft-soft interaction 21 . Recently, metal-organic frameworks (MOFs) [22][23][24][25][26][27][28] have been explored as a new type of adsorbents for mercury removal [29][30][31][32][33][34] due to their high surface areas, but they usually suffer from instability in water 29,30 or aqueous solutions with a wide pH range 34 and possess low adsorption capacity and weak affinity for Hg(II).…”

Coordination‐Driven Terpyridyl Phosphine Pd(II) Gels

“…[50,51] This suggests that moderate heating play a key role in triggering the formation of coordination-driven gels because mild heating boosts the reversibility of the coordination bonding and makes it comparable and competitive with respect to other supramolecular weak interactions. [51] …”