High Photocatalytic Efficiency of Al₂O₃-TiO₂ Coatings on 304 Stainless Steel for Methylene Blue and Wastewater Degradation

Round 1

Reviewer 1 Report

The authors describe the High photocatalytic efficiency of Al₂O₃-TiO₂ coatings on 304 stainless steel for methylene blue and wastewater degradation. There are several major as well as minor errors to be checked before its possible publication in "Catalysts".

1. The authors need to check the title of the manuscript.
2. The abstract should be rewritten more precisely without including unnecessary information. Try to highlight the novelty of the research and its contribution accurately.
3. The bacterial pathogen name should be in italics.  
4. The introduction is too lengthy.
5. Please clarify the innovations in this work in the introduction section.
6. In Figure 1: (i) Some of the peaks did not index; check it. For example: 40-45º, 78º, 75º peaks are not indexed.

(ii) The authors need to calculate the structural parameters, such as lattice constant, crystallite size, strain, etc., of the prepared samples and explain them in the text.

(iii) Should include the percentage of anatase and rutile phases of TiO₂.

(iv) If possible, include the XRD pattern for 304 SS sample.

7. In Figure 2: (i) The authors need to label the corresponding structures of Al₂O₃ and TiO₂ in the Al₂O₃/TiO₂ SEM image.

(ii) The EDAX spectrum of Al₂O₃/TiO₂ is not visible.

(iii) How did the authors find the thickness of the coating sample? There are no cross-sectional SEM images of the Al₂O₃/TiO₂ sample.

8. In Figure 3: Figure 3b caption is not elemental mapping. Roughness (Rq) analysis of the Al₂O₃/TiO₂ sample.
9. In Figure 4: (i) The authors need to include the absorbance spectra of without coating sample for comparison purposes.

(ii) Figure 4b: x-axis (energy / e. v) is it correct??

(iii) Why did the authors not mention optical bandgap in the Tauc’s plot graph and did not discuss in the text?

10. In table 1: (i) Include the morphology of the photocatalysts.

(ii) Add the unit of degradation efficiency.

(iii) Provide the reference for Al₂O₃/TiO₂ (1.5 Al/Ti).

11. In Figure 5a: Check the spelling of the y-axis (Metylenene blue).
12. In Figure 6: (i) The authors need to include the energy band diagram with photo degradation mechanism of Al₂O₃/TiO₂ composite.

(ii) "Membrana disruption" or "Membrane disruption"??

(iii) Should improve the bacterial inhibition growth mechanism using Al₂O₃/TiO₂ coating.

13. The authors need to provide the reusability of the prepared samples against MB dye.
14. One critical aspect to consider is the stability of the prepared materials, particularly for practical applications.
15. Post-filtration characterizations are required, e.g., XRD or SEM, to further prove the stability of the prepared sample.
16. The authors include their perspective on the future of this research in the conclusion section.
17. The authors can compare this research with other similar studies in a tabular format to highlight the advantages of their work.
18. The text is not free from grammatical, format, and punctuation errors. 

Minor editing of English language is required. 

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

This research work is interesting, it's analyzes a catalyst deposited on stainless steel by coating Method, however, I have some recommendations:

1.- It is necessary to improve the introduction with the effects of the coating Methods, because it is key in your research.

2.- Why used six stainless steel plates? What is the available contact area of catalyst in the six plates? It is important to explain it to know the effect of the area on degradation and mineralization.

3.- Scavenger experiments are needed to confirm the main reactive species, OH, O2-, e-, H+

4. Catalyst reuse cycles in the reaction system are important.

Author Response

Please see the attachment

Author Response File: Author Response.pdf