Preparation of ZnFe2O4@TiO2 Novel Core-Shell Photocatalyst by Ultrasonic Method and Its Photocatalytic Degradation Activity
Round 1
Reviewer 1 Report
The Authors submitted a report dealing with ZnFe2O4-TiO2 core-shell nanoparticles and their application for photocatalysis. Even though the Authors obviously did a lot of work, the manuscript does not reach the level required for scientific publication. Every manuscript must contain credible and concrete data, a suitable experiment description for reproducibility, as well adequate data evaluation and discussion. And, of course, the manuscript must be written in a clear and easy-to-understand way. This is missing in the submitted report. In details:
(1) Improper abstract
Already the abstract is a puzzle for the Reader. Thfore are no explanations of abbreviations. Some of them are explained later (TBOT is on the third page), and soIn addition, theof them (OFX) never. The abstract contains unclear information ("The pollutant concentration was..." what pollutant?) and useless information (material labels).
(2) Unclear language
The puzzle continues. The text is wria tten in not very scientific way ("Ninety mL" instead of "90 mL") with unclear parts ("ammonia water"). I cannot recognize TiO2 or ZnFe2O4 "monomer" either. These materials are not monomers/polymers, but they are bulk materials.
(3) Wrong discussion
I cannot accept if the Authors claim that TiO2 nanoparticles are "with uniform particle size" if the particle size ranges from 200 to 400 nm (see Fig. 2(b)). That is a very broad particle size distribution.
(4) Insufficient analysis
Some experiments were done; however, without proper evaluation are meaningless. For example, the electrochemical impedance spectra are plotted, but the electrical equivalent circuit analysis is missing. Hence, there is no information for the Reader.
As a result, I cannot presently support the manuscript. Therefore, I strongly recommend major changes of the manuscript and resubmission after proper modification.
Author Response
Please see the attachment.
Author Response File: 
Author Response.docx
Reviewer 2 Report
In this work, the authors synthesized ZnFe2O4@TiO2 novel core-shell photocatalyst by ultrasonic method, and its photocatalytic degradation activity was established using several hazardous pollutants such as RhB, MB, MO, Phenol, and OFX.
In general, the manuscript is well written, scientifically valid, and actual with state-of-the-art research methodology. But the manuscript lacks several technical things:
1. BET (specific surface area) and pore sizes in these types of heterogeneous catalysts play a major role in photocatalysis which must be added to the manuscript.
2. I can see some impurities in your EDS spectra, if I am not wrong it is Au, from where does it come? Give relevant justification.
3. What is the unit of the x-axis in Figure 2?
4. What do the boxes in Figure 5a signify? Also, add relevant miller indices to your XRD spectra for a better understanding of readers.
5. Regarding the photocatalytic performance: I suggest adding total organic carbon (TOC) measurements after photocatalysis to validate the mineralization of target compounds. Adding this will help your research more scientific and highly appreciable by the researchers in this area.
6. Finally, do you check the leaching of metal ions from the catalyst surface into the reaction media?
7. The use of UV irradiation makes the process quite expensive, why you haven't tried visible solar light to carry out your research?
Furthermore, there are many grammatical errors (check your subscripts). Based on the above points, I recommend major revisions to the manuscript for consideration in the journal of Coatings.
Author Response
Please see the attachment
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
The Authors modified the manuscript in accordance with the Reviewers" comments and/or suggestions; however, the electrochemical impedance spectroscopy (EIS) data are still not evaluated. I cannot accept the discussion on the recorded data without a proper evaluation of the meaning of the equivalent electrical circuit model. I am glad to see that the manuscript was improved a lot; however, if the EIS data are included and discussed, the proper analysis cannot miss. As a result, I cannot accept the manuscript in present form and I need to ask for minor changes.
Author Response
Point1: The Authors modified the manuscript in accordance with the Reviewers" comments and/or suggestions; however, the electrochemical impedance spectroscopy (EIS) data are still not evaluated. I cannot accept the discussion on the recorded data without a proper evaluation of the meaning of the equivalent electrical circuit model. I am glad to see that the manuscript was improved a lot; however, if the EIS data are included and discussed, the proper analysis cannot miss. As a result, I cannot accept the manuscript in present form and I need to ask for minor changes.
Response 1: To solve this problem, I went down and checked the data carefully, and gave a detailed explanation in the blue highlighted section on page 12 of the manuscript. I am very grateful to the reviewers for their recognition of my manuscript.
Reviewer 2 Report
The author's answers to my comments are satisfactory. Although, RhB dye can be mineralized and it doesn't cause such issues in the equipment as per my experience.
However, the authors did a great job and their work is recommended for publication.
Author Response
The author's answers to my comments are satisfactory. Although, RhB dye can be mineralized and it doesn't cause such issues in the equipment as per my experience.
However, the authors did a great job and their work is recommended for publication.
Response 1: I would like to thank the reviewers for recognizing my results and giving me such pertinent suggestions. The school has just started, and all our students are in isolation in the dormitory. I will carry out further research after it is unblocked. Thank you again for reviewing my paper during this period of time.
