Original Article:
Sodium citrate assisted hydrothermal synthesis of nickel cobaltate absorbers with tunable morphology and complex dielectric parameters toward efficient electromagnetic wave absorption
Ming Qin, et al.
Applied Surface Science, 2020, 504, 144480.
10.1016/j.apsusc.2019.144480
Nickel cobaltate (NiCo2O4) is a promising candidate for electromagnetic absorbers. The electromagnetic wave-absorbing performance of NiCo2O4 is closely related to its morphology and structure, and the morphology and structure of the material are closely related to the synthesis method. The hydrothermal method has been widely used in the synthesis of NiCo2O4 nanomaterials due to the simple shape-controlled manipulation by changing the reaction conditions, for example, addictive. So far, NiCo2O4 with various micro/nanostructures, including nanorods, microspheres, and urchin-like morphologies, have been prepared by hydrothermal synthesis.
Sodium citrate is an important additive in the hydrothermal process, and its carboxyl and hydroxyl groups can strongly chelate metal ions. Therefore, the reduction of free metal ions will slow down the nucleation rate and crystal growth of the precursors during the hydrothermal process, thereby affecting the morphology of the final product. In this work, sodium citrate was used as an additive to control the morphology and complex permittivity of NiCo2O4 absorbers by hydrothermal method. The size, porosity, and morphology of NiCo2O4 can be tuned by changing the ratio between sodium citrate and metal salt. The results showed that the morphology of NiCo2O4 evolved from 3D flower-like structure to 2D nanosheets with the increase of sodium citrate. Notably, the porosity and interconnected nanosheet layers are beneficial to facilitate electromagnetic wave absorption by dissipating electromagnetic waves through multiple reflections and scattering. This work may provide us with a new strategy to tune the effective absorption bands of other cobalt-based spinel-structured electromagnetic wave absorbing materials.
Chemicals Related in the Paper:
| Catalog Number | Product Name | Structure | CAS Number | Price |
|---|---|---|---|---|
| ACM61320403 | Sodium Citrate |  |
6132-04-03 | Price |
