Well‐Defined Metal–Organic Framework Hollow Nanocages

Abstract

Metal-organic frameworks (MOFs) have demonstrated great potentials in a variety of important applications. To enhance the inherent properties and endow materials with multifunctionality, the rational design and synthesis of MOFs with nanoscale porosity and hollow feature is highly desired and remains a great challenge. In this work, the formation of a series of well-defined MOF (MOF-5, Fe(II) -MOF-5, Fe(III) -MOF-5) hollow nanocages by a facile solvothermal method, without any additional supporting template is reported. A surface-energy-driven mechanism may be responsible for the formation of hollow nanocages. The addition of pre-synthesized poly(vinylpyrrolidone)- (PVP) capped noble-metal nanoparticles into the synthetic system of MOF hollow nanocages yields the yolk-shell noble metal@MOF nanostructures. The present strategy to fabricate hollow and yolk-shell nanostructures is expected to open up exciting opportunities for developing a novel class of inorganic-organic hybrid functional nanomaterials.

Surfactant-assisted ZnO processing as a versatile route to ZIF composites and hollow architectures with enhanced dye adsorption

“…( Figure S39) This is analogous to the acid-induced etching of Prussian Blue mesocrystals, where adsorbed layers of PVP significantly reduce the rate of etching on the outer surface leading to the controlled formation of hollow particles 29 , and the PVPstabilised template-free formation of MOF-5 derived hollow nanocages. 30 Further, the surface-functionalisation assisted etching of ZIF-8 using phenolic acids has recently been demonstrated 31 .…”

Evolution of form in metal–organic frameworks

“…1). Recently, similar synthetic efforts have been applied to metal–organic frameworks (MOFs), an emerging class of porous materials222324252627282930313233343536. However, unlike other micro-/nanostructures reported in metal/metal oxide systems, those in MOFs are still in their infancy, as evidenced by the fact that the vast majority of these materials have hollow forms, an early stage of form evolution (Fig.…”

“…1)37. The synthetic strategies identified for hollow MOFs include templating methods (using polystyrene beads2526, emulsion droplets27, CO 2 bubbles28, MOFs29 and metal–organic polyhedron (MOP) crystals30), interfacial growing methods31, spray-drying techniques32 and surface-driven mechanisms33. A recent notable example from Lah group utilizes MOP crystals as a sacrificial template to synthesize hollow MOFs30.…”

Application of metal and metal oxide nanoparticles@MOFs

“…Separation by adsorption is more energy efficient than distillation, but to date limited examples with acceptable selectivity have been reported [184]. Silica is the most common stationary phase used in normal phase chromatography and therefore, a natural step forward is to combine silica and MOFs to achieve better performances.…”