Highly efficient and broad electromagnetic wave absorbers tuned via topology-controllable metal-organic frameworks

Abstract

Advanced electromagnetic (EM) wave absorbing materials with strong absorption and broad bandwidth are important for military stealth and elimination of microwave pollution in consumers' electronics. Metal organic framework (MOF)-derived metal/carbon hybrids with ordered structure are significantly urgent in this field. In this contribution, we presented a design strategy of hollow cage-like or solid boxlike magnetic/dielectric Fe/Co/C and dielectric Fe/Mn/C EM wave absorbing nanomaterials via pyrolyzing Prussian blue's analogs with controllable topology and phase composition. The solid box-like Fe/Co/C and hollow cage-like Fe/Mn/C showed favorable absorption property with a broad effective absorption bandwidth (EAB) and a low reflection loss (RL).Especially, the EAB of 8.8 GHz at a thickness of 2.5 mm for solid box-like Fe/Co/C nanocomplex prepared at 900°C is a new record for this type of materials. The design and tuning strategy for EM wave absorbers derived from topology-controllable MOF is important for EM functional materials possessing great potential in military stealth and consumers' electronics.

Direct Z-scheme α-MnO2@MnIn2S4 hierarchical photocatalysts with atomically defined junctions for improved photocatalytic activities

“…Importantly, the photogenerated electrons generated by semiconductors with a deeper conduction band top have extremely strong reducibility and have attracted the attention of researchers. 3 , and metal-Mn LDH) are widely used in photocatalytic environmental remediation, supercapacitors, lithium-sulfur batteries, and guided cancer treatments due to their low-cost and easy availability, environmental friendliness, high theoretical capacitance, and narrow band gap [23][24][25][26][27] . Among them, the visible light absorption capability of manganese oxide is high due to its narrow band gap which makes it a promising candidate for photocatalysis.…”

Research on dielectric and microwave absorbing properties of TiO2/TiB2/Thermoplastic polyurethanes (TPU) composite materials

“…The dielectric constant and permeability of T15−T30 were carried out using the vector network analyzer (VNA, MS4644A, Anritsu, Atsugi, Japan) by the coaxial line method in 2−18 GHz. The EM wave absorption ability is indicated by the RL, which can be signified using equations ( 1) and ( 2) [8]:…”

Composition Optimization and Microstructure Design in MOFs-Derived Magnetic Carbon-Based Microwave Absorbers: A Review

“…By comparison, polyvinyl pyrrolidone (PVP) seems to be a microstructure directing agent with good universality for different hollow MOFs and, to date, hollow Ni-1,3,5-trimesic acid microspheres (Fig. 8 d, e), FeMn PBAs nanoboxes, and FeCo PBAs nanoboxes have been successfully fabricated with the assistance of PVP [ 32 , 145 , 146 ]. The resultant Ni/C, FeMn/C, and FeCo/C composites with typical hollow microstructure all produce better EM absorption performance than their solid counterparts.…”