Synthesis of Controllable Nickel Chalcogenide Nano‐Hollow Spheres and Their Tunable Absorbing Properties

Abstract

A series of nickel chalcogenide compounds (NiS2, NiS, NiO and NiSe2) with nanoscale hollow sphere structure have been successfully designed and fabricated by a simple and effective hydrothermal process. By appropriately adjusting the reaction temperature, we have obtained chalcogenide nickel nanomaterials with uniform size and controllable morphology. Subsequently, the electromagnetic wave absorption properties of nickel chalcogenide nano‐hollow sphere compounded with paraffin and polyvinylidene fluoride (PVDF) were investigated in a frequency range of 2–18 GHz. Under the same filling amount, the optimal absorbing performance of PVDF‐based composites can all exceed −10dB, which is significantly better than paraffin‐based composites. Therefore, PVDF‐based composites are more conducive to microwave absorption performance than paraffin‐based composites. Interestingly, the optimal effective frequency bandwidth of NiS/PVDF nanocomposites with 20 wt% filler content covers 5.0 GHz at a thin coating layer of 2.0 mm, and the corresponding reflection loss value can reach −36.3 dB at 15.2 GHz. Moreover, the fundamental attenuation mechanisms are discussed in detail.

Self-Stacked Growth of Cu9S5 Nanostructures with Morphology Regulation as an Electromagnetic Wave Absorber

“…Figure b shows the performance of CS-3 at 1.78 mm compared with other semiconductor sulfides. Combined with previous studies, ,,− the performance of polyhedral Cu 9 S 5 was still relatively excellent. Among them, WS 2 and VS 2 had an EAB less than 2 GHz, so they were expressed here as 2 GHz.…”

NiO/Ni Heterojunction on N‐Doped Hollow Carbon Sphere with Balanced Dielectric Loss for Efficient Microwave Absorption

“…Furthermore, specific reflection loss (S RL ) is an indicator which is more appropriate to evaluate microwave absorbing performance. The S RL value of NHCS@NiO/Ni could reach 220.2 dB mg −1 mm −1 much larger than those of other previously reported absorbers including hollow carbon sphere, [ 45 ] NiS 2 hollow spheres, [ 46 ] hollow Ni nanosphere, [ 47 ] NiFe 2 O 4 hollow nanosphere, [ 45 ] carbon hollow spheres, [ 48 ] hollow carbon sphere, [ 49 ] NiCo 2 O 4 hollow sphere, [ 50 ] S‐doped hollow sphere, [ 51 ] NiO/NiFe 2 O 4 /Ni foam, [ 52 ] and Ni/NiO/Cu@C [ 53 ] (Figure 5l and Table S2, Supporting Information). In addition, the attenuation constant (α) mainly represented the microwave dissipation capability by dielectric loss, which higher α value was attributed to stronger dissipation ability.…”

Dependence of Transition-Metal Telluride Phases on Metal Precursor Reactivity and Mechanistic Implications

“…The amine in most cases should be a stronger ligand than the halides, and ligand substitution may make metal centers more inert or labile, depending on their unique d electron counts and coordination geometry. For example Co(II), d 7 , amine complexes are likely to have octahedral coordination requiring a dissociative mechanism, and so additional amine would inhibit the reaction with the tellurium precursor. On the other hand Ni(II), d 8 , can support four-coordination environments and be open to associative mechanisms.…”

“…Yet metal tellurides are important materials from an application standpoint. Iron, , cobalt, , and nickel , chalcogenides have a variety of applications as mercury capture materials, superconductors, catalysts, and electromagnetic wave absorption materials. Additionally, ruthenium, , palladium, , and platinum , chalcogenides have uses as catalysts, electrocatalysts, and suppressors of magnetoresistance.…”