Beyond Pristine Metal–Organic Frameworks: Preparation of Hollow MOFs and Their Composites for Catalysis, Sensing, and Adsorption Removal Applications

Abstract

Metal–organic frameworks (MOFs) have been broadly applied to numerous domains with a substantial surface area, tunable pore size, and multiple unsaturated metal sites. Recently, hollow MOFs have greatly attracted the scientific community due to their internal cavities and gradient pore structures. Hollow MOFs have a higher tunability, faster mass-transfer rates, and more accessible active sites when compared to traditional, solid MOFs. Hollow MOFs are also considered to be candidates for some functional material carriers. For example, composite materials such as hollow MOFs and metal nanoparticles, metal oxides, and enzymes have been prepared. These composite materials integrate the characteristics of hollow MOFs with functional materials and are broadly used in many aspects. This review describes the preparation strategies of hollow MOFs and their composites as well as their applications in organic catalysis, electrochemical sensing, and adsorption separation. Finally, we hope that this review provides meaningful knowledge about hollow-MOF composites and their derivatives and offers many valuable references to develop hollow-MOF-based applied materials.

Advances and Outlook of Metal–Organic Frameworks as High-Performance Electrocatalysts for Hydrogen Evolution Reaction: A Minireview

“…Despite the significant progress made in developing efficient electrocatalysts based on MOF-based composites with excellent properties and unique structures, , there is still a long way to go before they can be designed and fabricated for widespread industrial uses in the production of hydrogen. Stability is also a crucial factor that needs to be considered for its applicability in the electrochemical field …”

Ingenious microenvironment regulation of a metal–organic framework (MOF) nanoreactor for electrochemical detection of chlorogenic acid

“…Compared to original MOFs, HMOFs present the advantages of faster mass transfer, richer active sites and better compatibility. 12 It should be emphasized that most of the original MOFs (HMOFs) exhibit poor conductivity and redox activity. 13 Therefore, it is necessary to assemble these MOFs with guest materials to achieve excellent properties.…”

Synthesis and characterization of hollow dual-tube MOF hybrid nanocomposites for electroanalytical applications

“…[6][7][8] Additionally, the benefits of ZIF-8 with the hollow structure (e.g., richer porosity, faster mass transfer characteristics, and better compatibility under harsh conditions) were often easily overlooked. 9 It is worth further emphasizing that a calcination atmosphere (air or oxygen or inert) can rapidly obtain the desired hollow structure, but this tends to disrupt the crystal structure features of MOFs, preventing them from sustaining their original crystal structure. Therefore, the predictable construction of ZIF-8 with unique morphological features, followed by the controllable preparation of hollow ZIF-8 (HZIF-8) using easily accessible and non-destructive crystal structure strategy, is a hot topic of great interest to scientists.…”