Micro-Structural Design of CoFe2O4/SWCNTs Composites for Enhanced Electromagnetic Properties
Round 1
Reviewer 1 Report
Referee report on “Micro-structural design of CoFe2O4/SWCNTs composites for enhanced electromagnetic properties" by Zaoxia Houet al.
Although this topic is of some interest, this manuscript in its present form cannot be recommended for publication and requires at least some improvement.
1. Line 45. For broad generality and to attract more readers, it would be important to note/mention materials for radiation protection. See, recent MDPI paper and references therein: Kozlovskiy, A.; Shlimas, D.I.; Zdorovets, M.V.; et al. Materials 2022, 15, 6071. https://doi.org/10.3390/ma15176071
2. in the introduction, it is necessary to briefly mention the effects associated with porosity, because pores are present in a large class of synthesized materials, including spinels:
Klym, H.; Karbovnyk, I.; Luchechko, A.; Crystals 2021, 11, 1515. https://doi.org/10.3390/cryst11121515
3. Again, for broad generality, it would be helpful to provide more background information about CoFe2O4. See, as an example, one of the recent reviews:
Sharifianjazi, F., Moradi, M., Parvin, N., et al (2020). Magnetic CoFe2O4 nanoparticles doped with metal ions: a review. Ceramics International, 46(11), 18391-18412.
4. Fig. 1. It would be useful to show the scale.
5. How will equations 1 and 2 work in highly porous materials?
6. The quality of Fig. 8 (a-d) is poor, not all details are distinguishable.
7. Fig 10 (insert) needs to be improved.
8. Fig.11 needs numeric (in order of magnitude) parameters.
Author Response
Please see the attachment
Author Response File: 
Author Response.docx
Reviewer 2 Report
The paper reportsCoFe2O4/SWCNTs composites with well-designed necklace-like structure for electromagnetic wave absorption materials. I agree that here we observe combination of dielectric loss and magnetic loss, which makes the paper quite interesting.
Recommended to publish in the present form.
Author Response
Thank you very much!
Reviewer 3 Report
In this research, necklace-like CoFe2O4/SWCNTs nanocomposites were architected through a solvothermal scenario by regulating the mass ratio of the magnetic part. The tailored structures were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM), vibrating sample magnetometer (VSM), and X-ray photoelectron spectra (XPS). Eventually, the microwave absorbing features were investigated from 2 to 18 GHz, illustrating a maximum reflection loss (RL) of -42.07 dB at 14.30 GHz with an efficient bandwidth (RL≤-10 dB) of 3.80 GHz, where the matching thickness was 1.50 mm.
There are several points that the authors should consider:
1. The authors have stated that “The experimental parameters (cobalt salt gradient (0.2g, 0.25g, 0.3g, 0.35g as Co-1, Co-2, Co-3, Co-4) where carbon nanotubes were 4mg) were adjusted to achieve the modulation of the microstructure of spinel ferrites, to investigate the effect of microstructural changes on the absorbing properties of the samples.” The stoichiometric amount of iron and cobalt salts is needed to fabricate CoFe2O4. Why the authors have mentioned the amount of cobalt salt is changed? Why is the microstructure modulated by regulating the ratio of cobalt salt? More explanations are needed.
2. Why by enhancing the cobalt ratio the saturation magnetizations fluctuate? It is expected that Ms be augmented by increasing the magnetic phase. Please add more discussions.
3. Please provide impedance matching and Cole-Cole curves and accordingly interpret the achieved results (DOI= 10.1016/j.carbon.2022.06.037; 10.1016/j.jallcom.2022.163792; 10.1016/j.ceramint.2020.05.139; 10.1088/1361-6528/abb2c0; 10.1002/advs.202105553).
4. It is well known that morphology, phase, and defect play a vital role in tuning the electromagnetic features of microwave absorbers. As stated by the authors, “necklace-like CoFe2O4/SWCNTs nanocomposites were prepared by the solvothermal method”, please discuss the trade-off between microwave absorption and the aforementioned key factors and untangle the introduction based on the presented approach (DOI= https://onlinelibrary.wiley.com/doi/abs/10.1002/adfm.202108194; 10.1002/adma.202107538; 10.1016/j.carbon.2021.11.045; 10.1016/j.jcis.2021.08.186; 10.1016/j.polymer.2020.122981; 10.1016/j.jallcom.2021.159039; https://www.sciencedirect.com/science/article/abs/pii/S1385894720322178; 10.1016/j.jallcom.2020.156453; 10.1002/adma.202106195; 10.1007/s10853-021-06394-z). Particularly, please promote the introduction based on the cutting-edge literature discussing the state-of-the-art susceptibility related to the other morphologies of carbonaceous microwave absorbing materials as well as the methods applied to anchor the oxygen-containing functional groups onto the carbon-based structures (DOI= 10.1007/s40820-022-00906-5; 10.1016/j.cej.2022.136903; 10.1088/1361-6528/abc2ec; 10.1088/1361-6528/abe0e4; 10.1016/j.cej.2020.126985; 10.1038/s41598-021-91370-5).
5. What is the reason behind the observed negative parts in permeability? (DOI= 10.1016/j.coco.2020.100421; 10.1016/j.jallcom.2020.157273)
Author Response
Please see the attachment
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
The authors have significantly and successfully improved the initial version of their manuscript, which now can be recommended for publication.
Reviewer 3 Report
The revised version can be published.
