In recent years, metal-organic frameworks (MOFs)-derived composites have emanated as a significant class of substantial materials with specific functional characteristics such as flexibility, high porosity, and diverse composition. Specific chemical modifications can also endow MOFs with specific functionality by offering the possibility of manufacturing all new generation of sensing devices. As on comparison with pure MOFs, the mix up of MOFs with matrix materials(e.g., metal nanoparticles, quantum dots, molecular species, enzymes, silica, and polymers) or functional species not only exhibits enhanced properties, but also widens its applications to modern field of heterogeneous catalysis, gas separation, potential hydrogen storage material and many others due to its high adsorption nature and excellent reversibility kinetics as in result reveals its various undefined attributes, such as reproducible syntheses, amenability to scale-up and chemical modification due to interactions of the functional matrix or species with the MOFs structures.
Top1. Introduction
In recent decades, the synthesis of metal-organic frameworks (MOFs) has gained tremendous attention due to the potential of achieving a wide range of esthetically appealing structures that exhibits considerable interest to applications in a range of porous materials fields. Based on pore size, shapes these MOFs have gained a promising traditional application in the field of storage, catalysis and separation as of the host-guest interactions(Stock & Biswas, 2012). A metal-organic framework material (MOF) consisting of two main components which are a metal ion (or metal ion cluster) and an organic molecule (or bridging ligands).
Metal ions + Organic units (bridging ligands) → MOF materials
Organic ligands may be defined as species which donate to metal ions multiple lone pairs of e-, while metal ions having vacant orbital shells accept these lone pairs of electrons results in formation of non-organic frame material(X. Liu, Sun, Hu, & Wang, 2016).
With such functionality, MOFs are used as integrated with the structural, electrical, magnetic and catalytic properties developed by selecting suitable metal ions and organic ligands (Adhikari & Lin, 2016). With researcher’s efforts, various synthetic techniques have been developed to form the MOFs having various crystal structures, surface chemistries and pore size/shapes. On comparison with other porous materials such as mesoporous silica and zeolites, it deliver better chemical tailoring capabilities such as separation, molecular storage and catalysis attributed to their existence of various functional groups inside their frameworks. For applications like catalysis, MOFs are necessary which are generated by synthetic room temperature techniques, because MOFs synthesized at low temperatures terms out to be extremely thermal stable. Initially the researchers from the coordination and solid-state / zeolite chemistry fields carried out the research of MOFs (Lin, Adhikari, Lin, & Tu, 2016). Now days, MOFs are also attracting attentions of material scientists. Several scientists have introduced a post-synthetic modification of MOFs via a sequence of chemical reactions to incorporate the functionalities and creation of composite materials that appear to impart features in MOFs via the incorporation of functional species like organic colours, minor bio-molecules, NWs, NPs, polymers and nanofibers through the composite formation(Yang, 2005). MOF composites can be formed by two means: a) by deposition of MOFs to create the thin films on a two-dimensional planar substratum; b) by combining MOFs with the other components to create mixed structures.
The preparations and applications of MOF films occurred on various substrates have been applied by many chemists in various fields. This chapter will therefore concentrate on a concise overview of MOF composite materials preparation (Ben, Lu, Pei, Xu, & Qiu, 2012). Techniques utilized for MOF composites synthesis according to their formulation phase have been discussed throughout the chapter. Figure 1 showing various applications of MOFs composites.
Figure 1. Applications of MOFs composites in various fields