Heterogeneous Nanosized Metal (Metallic Compound)@Metal‐Organic Framework Composites: Recent Advances in the Preparation and Applications

Abstract

Metal‐organic framework (MOF) composites based on MOFs‐wrapped metals or metallic compounds (denoted as M/MC@MOFs) are an important class of materials that integrate M/MCs and MOFs. MOFs can fix and confine M/MCs to regulate their size, prevent uncontrollable aggregation, and enhance the exposure and ordered arrangement of active sites. In turn, M/MCs support the MOFs to enhance their stability and realize more targeted properties. In this review, the features and application scope of different M/MC@MOF synthesis methods are explored, considering the influential factors and regulation modes of the M/MC–MOFs integration. Additionally, the performances of the M/MC@MOF composites are comprehensively discussed, and the underlying mechanisms are clarified. The performance of M/MC@MOFs is dependent on the orderly synergy between the MOFs and M/MCs. MOFs can sieve and transfer specific molecules to the M/MC surface, whereas the robust interface provides new charge/energy‐transfer pathways, which enhance the activity and selectivity of the composites for diverse molecules. Furthermore, the challenges facing this field are analyzed, and the recommendations for advancing the development of M/MC@MOF composites are presented.

Third-Order Nonlinear Optical Modulation Behavior of Photoresponsive Bimetallic MOFs

“…With the development of optics and optoelectronic technology, metal–organic frameworks (MOFs) have attracted much attention in the field of third-order nonlinear optics (NLO) due to their customizable structures and flexible coordination modes. − In previous reports, the design strategy for MOFs with excellent NLO performance was typically aimed at the modification of ligands, such as extending the π-conjugated length of the ligands or introducing strong electron donor/acceptor groups. − Notably, charge transfer between ligands and metal ions (including metal to ligand and ligand to metal) is considered a key factor affecting the nonlinear performance of MOFs. − However, the single metal node and uniform charge density distribution often lead to low efficiency between ligands and metal ions; − therefore, constructing bimetallic cooperative MOFs is an effective strategy to regulate charge transfer from the aspect of the internal structure and improve the performance of third-order NLO. , …”

Ingenious Modulation of Third-Order Nonlinear Optical Response of Zr-MOFs through Defect Engineering Based on a Mixed-Linker Strategy

“…Third-order nonlinear optical (NLO) materials have been widely used in laser protection, biological imaging, photodynamic therapy, and logic devices. − Metal–organic frameworks (MOFs) exhibit exceptional potential for applications in the field of nonlinear optics owing to their customizable structure, adjustable electronic properties, and facile modifiability. − Currently, primitive MOFs are limited to a single charge transfer path either from metal to ligand or from ligand to metal, resulting in low efficiency of electron transfer. , Defect tuning in MOFs is an effective approach to address this issue. It is widely embraced to promote the properties of diverse materials, regulate their surface characteristics, and bestow novel and practical functionalities upon them. , The introduction of defects into MOFs can not only lead to a cascade of transformations, including the rupture and recombination of chemical bonds and distortion and rearrangement of electron clouds, but also engender new pathways for charge transfer, thereby effectively augmenting charge transfer efficiency. − The charge transfer efficiency is widely acknowledged as the pivotal factor influencing the performance of NLO, which possesses the potential to effectively regulate and optimize the overall functionality. − …”

Controllable Modulation of Third‐Order NLO Properties by Polymer‐Modified MOFs Core@Shell Nanoarchitecture

“…MOF-based heterostructures, which combine the inherent properties of MOFs with the specific advantages of functional materials, are currently a popular research direction in various fields. [1][2][3] In particular, heterogeneous interface brings additional electron transfer paths through tight interfacial contact synergies, which is conducive to surface electron modulation and electron redistribution. [4][5][6] Thus heterogeneous interface engineering is an effective strategy to improve the performance in catalysis, batteries, biosensing, etc.…”