State of the Art and Prospects in Metal-Organic Framework-Derived Microwave Absorption Materials

Abstract

Microwave has been widely used in many fields, including communication, medical treatment and military industry; however, the corresponding generated radiations have been novel hazardous sources of pollution threating human’s daily life. Therefore, designing high-performance microwave absorption materials (MAMs) has become an indispensable requirement. Recently, metal–organic frameworks (MOFs) have been considered as one of the most ideal precursor candidates of MAMs because of their tunable structure, high porosity and large specific surface area. Usually, MOF-derived MAMs exhibit excellent electrical conductivity, good magnetism and sufficient defects and interfaces, providing obvious merits in both impedance matching and microwave loss. In this review, the recent research progresses on MOF-derived MAMs were profoundly reviewed, including the categories of MOFs and MOF composites precursors, design principles, preparation methods and the relationship between mechanisms of microwave absorption and microstructures of MAMs. Finally, the current challenges and prospects for future opportunities of MOF-derived MAMs are also discussed."Image missing"

Hierarchical Multi-Core–Shell CoNi@Graphite Carbon@Carbon Nanoboxes for Highly Efficient Broadband Microwave Absorption

“…In this study, the multiple heterogeneous interfaces brought about by the multi-core–shell structure realize the charge accumulation and thus achieve the interfacial polarization loss. Meanwhile, under the action of external electric field, the polar molecules and surface charges lead to the dipole polarization loss . When ε ″ values get large, four straight lines appear, which correspond to the conduction loss mainly caused by GC. , To conclude, the dielectric loss of the composite is strongly associated with polarization loss and conduction loss …”

“…With the rapid development of the information age, adverse electromagnetic radiation gradually endangers human health and interferes with the normal use of some electronic instruments. − To solve this serious problem, it is urgent and critical to develop high-performance microwave absorbing materials (MAMs). , For MAMs, they are required to possess the features of thin thickness, light weight, a wide absorption frequency band, strong absorption, and attenuation of electromagnetic waves (EMWs) . Depending on their loss mechanism, MAMs are mainly classified into dielectric loss materials and magnetic loss materials. , However, the currently available MAMs with a single loss mechanism cannot meet all the requirements simultaneously as mentioned above . Hence, in response to this development, manufacturing MAMs with dual loss mechanisms has become a priority in the latest research. − …”

“…As is known to all, it is still necessary and vital to realize the ideal design and construction of the absorbent’s microstructure in an efficient way, which may induce more energy loss in the transmission process of EMWs. , Recently, considerable efforts have been directed to the intended manufacturing of core–shell, yolk–shell structure, and hollow construction, all of which are now under development. Core–shell structures have been intensively investigated in this context because they are capable of realizing the integration of physicochemical qualities from both the core and shell layers. , Moreover, the design of a core–shell structure can generate more heterogeneous interfaces, which will result in an increase in polarization loss. For example, Co@SiO 2 @C core–shell nanocomposites and core–shell CoO/Co@C nanocomposites manifested excellent electromagnetic attenuation characteristics.…”

Micro-Opening Ridged Waveguide Tumor Hyperthermia Antenna Combined with Microwave-Sensitive MOF Material for Tumor Microwave Hyperthermia Therapy

“…28 For example, Ceren et al synthesized spherical porous ZrMOF by continuous flow spray drying. 29,30 However, MOF materials prepared by conventional spray methods are often micrometersized, and the excessively large particle size limits their application in the biological field. To solve this problem, we explored in this study an improved spray pyrolysis method, focusing on the efficient and rapid synthesis of nanoscale MOF materials to promote further development of MW sensitizers for tumor MW hyperthermia.…”

“…The size, location, and complex biology of tumors make it difficult to effectively control the tumor temperature. , To solve this problem, researchers have developed a series of MW sensitizers, among which metal–organic frameworks (MOFs) − have shown ultrahigh MW-heat conversion efficiencies, improving the outcomes of MW treatment. ,, The common preparation methods of MOFs are often time-consuming and low in efficiency; ,− thus, researchers have been searching for fast and efficient MOF synthesis methods and exploring new MOFs for clinical tumor treatment. − Spray pyrolysis is a green rapid synthesis method with broad application prospects, which may potentially be the sought for fast and efficient MOF synthesis method . For example, Ceren et al synthesized spherical porous ZrMOF by continuous flow spray drying. , However, MOF materials prepared by conventional spray methods are often micrometer-sized, and the excessively large particle size limits their application in the biological field. To solve this problem, we explored in this study an improved spray pyrolysis method, focusing on the efficient and rapid synthesis of nanoscale MOF materials to promote further development of MW sensitizers for tumor MW hyperthermia.…”