Fabrication of Nano-Ag Encapsulated on ZnO/Fe₂V₄O₁₃ Hybrid-Heterojunction for Photodecomposition of Methyl Orange

Round 1

Reviewer 1 Report (Previous Reviewer 2)

The reviewer doesn't see any major change compared to sustainability-1927664 revised version.

Author Response

Response to reviewer comments

Manuscript id: sustainability-2021832

Reviewer-01

Comments and Suggestions for Authors

The reviewer doesn't see any major change compared to sustainability-1927664 revised version.

Dear Reviewer,

Thank you for your comment. As per your previous comments, the manuscript was revised and submitted.

 

 

Author Response File: Author Response.pdf

Reviewer 2 Report (New Reviewer)

In this manuscript, the authors report Ag-ZnO/Fe₂V₄O₁₃ nanocomposites are highly active for photocatalytic degradation of Methyl Orange. The catalyst in this manuscript showed outstanding performance in the removal of Methyl Orange. However, some issues and revisions should be addressed before the acceptation. The specified comments are as following.

1. From Fig.10, why dye/ZnO/Fe₂V₄O₁₃/UV light system is better than dye/Ag-ZnO/Fe₂V₄O₁₃/UV light system with different percent wt of Ag loading (1wt% and 2.5 wt%)

2. The degradation kinetic constants for various Ag-ZnO/Fe₂V₄O₁₃ catalysts with different percent wt of Ag loading should be given in Figure 10. The authors should further explain these phenomenon.

3. I think the prepared materials such as ZnO/Fe₂V₄O₁₃ (FT-IR, XRD ,UV-vis-DRS) should be characterized, since it seems that only the best catalyst was characterized and analyzed in more depth.

4. The total ion chromatogram of the degradation intermediates should be provided when using GC/MS.

5. In section 3.10, the spent catalyst should be further characterized.

6. The concentration of different scavengers such as, TBA (OH scavenger), KI (h⁺ scavenger), BQ (O^2– scavenger) and AgNO₃ (e^– scavenger) should be mentioned in the text, respectively. 

Author Response

Response to reviewer comments

Manuscript id: sustainability-2021832

Reviewer -02

Comments and Suggestions for Authors

In this manuscript, the authors report Ag-ZnO/Fe2V4O13 nanocomposites are highly active for photocatalytic degradation of Methyl Orange. The catalyst in this manuscript showed outstanding performance in the removal of Methyl Orange. However, some issues and revisions should be addressed before the acceptation. The specified comments are as following.

Dear Reviewer.

We would like to thank you for your prompt consideration of our manuscript. We are happy to hear that you have given us an opportunity to revise the manuscript. Based on the

comments raised by you; we have revised our manuscript as possible as we could.

 

The following is the reviewer’s original comments and the details about our revision.

1. From Fig.10, why dye/ZnO/Fe2V4O13/UV light system is better than dye/Ag-ZnO/Fe2V4O13/UV light system with different percent wt of Ag loading (1wt% and 2.5 wt%)

Thank you for your comment. At particular time interval (until 60 min), there was no significant degradation efficiency difference between dye/ZnO/Fe₂V₄O₁₃/UV light system and dye/Ag-ZnO/Fe₂V₄O₁₃/UV light system (1wt% and 2.5 wt%). However, at the time of 120 min irradiation, the undoped system has little higher activity than 1wt% and 2.5 wt% of Ag loaded system. This may be due to surface blacking effect of ‘Ag’ on the catalyst.

2. The degradation kinetic constants for various Ag-ZnO/Fe2V4O13 catalysts with different percent wt of Ag loading should be given in Figure 10. The authors should further explain these phenomenon.

As suggested, Fig10 was modified and revised the text also.

3. I think the prepared materials such as ZnO/Fe2V4O13 (FT-IR, XRD, UV-vis-DRS) should be characterized, since it seems that only the best catalyst was characterized and analyzed in more depth.

Thank you for your suggestion. The detailed characterization of  Fe₂V₄O₁₃/ZnO was reported in our previous papers [22,31,32].

4. The total ion chromatogram of the degradation intermediates should be provided when using GC/MS.

Thank you for your comments. For review purpose, the ion chromatogram of the degradation intermediates is given below. And also included in supporting information Fig.S5 to S8

GC-MS spectrum of intermediate C₁₃H₁₃N₃O₃S (D1)R.T-19.796

 

 

 

GC-MS spectrum of intermediate C₁₂H₉N₂NaO₃S (D2)R.T-18.533

 

 

 

 

 

 

 

GC-MS spectrum of intermediate C₆H₅N₂NaO₃S (D3), R.T-16.665

 

 

 

 

 

 

GC-MS spectrum of intermediate C₆H₇NO (D4), R.T-15.512

 

 

 

 

 

 

 

 

5. In section 3.10, the spent catalyst should be further characterized.

As suggested, the spent catalyst was characterized by XRD and included in Fig .11.

 

6. The concentration of different scavengers such as, TBA (OH scavenger), KI (h+ scavenger), BQ (O2– scavenger) and AgNO3 (e– scavenger) should be mentioned in the text, respectively.

As suggested, the scavenger’s concentrations are provided in the text.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report (New Reviewer)

The questions have been well responed. This manuscript can be accepted in present form.

Author Response

Response to Editor’s comments

Manuscript id: sustainability-2021832

Editor’s comment,

There were two important issues pointed in this manuscript. One is poor
quality of pore-diameter distribution from BET results. Editor kept ask
the authors to provide better quality of data, but they just replied
only 4 data points what they got from Taiwan institute. Re-measurement
was expected, but no further action is quite disappointing. This is
quite difficult to ignore in the reviewing process. We hope they get
much higher quality of data supporting their conclusions from now on.
The other is discrepancy between EDX and stoichiometric ratio of Fe:V
(=1:2), which could be explained by vanadium deficiency in the lattice.
The reference literatures they cited look reasonable. This is a good
thing in this resubmitted manuscript.

Respected Editor,

Thank you for your comments. We have rechecked the source file of the BET results and got a few more points. So, redraw the diagram and included it in the revised manuscript.

 

 

Response to reviewer comments

Manuscript id: sustainability-2021832

Reviewer-02 (Round 2)

The questions have been well responed. This manuscript can be accepted in present form.

Respected Reviewer,

Thank you for your comment.

 

Author Response File: Author Response.pdf

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

The manuscript entitled " Fabrication of nano Ag encapsulated on ZnO/Fe2V4O13hybrid- 1 heterojunction for photodecomposition of Methyl Orange” within the scope of sustainability. I appreciate the authors for the preparation. However, the article is requiring revision to be published in the journal.

 Reviewer comment 1:

The manuscript is written well, but grammar and typo errors should to be done extensively?

Reviewer comment 2:

Minor issues: The abbreviations mentioned in the text.

Reviewer comment 3:

Abstract, the aim, and Conclusion should be rewritten..—

Reviewer comment 4:

The introduction part of the manuscript should be included " Advantages of using nanoparticles in dyes removal (update reference).

Reviewer comment 5:

Line 102 the authors need to show how they find the crystallinity size of Ag-ZnO/Fe₂V₄O₁₃

Reviewer comment 6:

The author needs a statistical analysis error bar in Figure 10.

Author Response

Response to Reviewer 1

Comments and Suggestions for Authors

 Dear Prof.

We would like to thank you for your prompt consideration of our manuscript. We are happy to hear that you have given us an opportunity to revise the manuscript. Based on the comments raised by the reviewer, we have revised our manuscript as possible as we could. The following is the reviewer’s original comments and the details about our revision.

 

The manuscript entitled " Fabrication of nano Ag encapsulated on ZnO/Fe2V4O13hybrid- 1 heterojunction for photodecomposition of Methyl Orange” within the scope of sustainability. I appreciate the authors for the preparation. However, the article is requiring revision to be published in the journal.

Dear Reviewer,

Ans: Thank you for your comments and your comments will help us to improve the quality of our manuscript.

 Reviewer comment 1:

The manuscript is written well, but grammar and typo errors should to be done extensively?

Ans: Thank you professor for your comment. As per your suggestion, the manuscript was thoroughly checked and typo and grammatical errors have been rectified.

Reviewer comment 2:

Minor issues: The abbreviations mentioned in the text.

Ans: The suggested abbreviations have been added in the revised manuscript.

Reviewer comment 3:

Abstract, the aim, and Conclusion should be rewritten. —

Ans:As suggested, the abstract, aim and conclusion have been revised.

Reviewer comment 4:

The introduction part of the manuscript should be included “Advantages of using nanoparticles in dyes removal (update reference).

As suggested, the dye removal related references have been added at introduction part in the revised manuscript.

Reviewer comment 5:

Line 102 the authors need to show how they find the crystallinity size of Ag-ZnO/Fe₂V₄O₁₃

The Scherrer equation (eqn. 1) was employed for the calculation of the average crystallite size of 2 wt% of Ag-ZnO/Fe₂V₄O₁₃ and it is found to be 28.5 nm.

D = kl/bcosq      … (1)

Where D is the crystalline size, λ is wavelength X-ray used; K is the shape factor, b is the full width half maximum high of peak and q is the Bragg angle. This has been included in the revised manuscript.

Reviewer comment 6:

The author needs a statistical analysis error bar in Figure 10.

As suggested, the suggested statistical analysis error has been added in the revised manuscript.

 

 

 

 

Author Response File: Author Response.docx

Reviewer 2 Report

Please provide more background information, and address the comments.

Comments for author File: Comments.pdf

Author Response

Response to Reviewer 02

 Dear Prof.

We would like to thank you for your prompt consideration of our manuscript. We are happy to hear that you have given us an opportunity to revise the manuscript. Based on the comments raised by the reviewer, we have revised our manuscript as possible as we could. The following is the reviewer’s original comments and the details about our revision.

Page 1, line 40 – 48. More references should be added to support the arguments here.

Ans: Thank you professor for your comment. As per the reviewer comment the references added and the manuscript was revised.

14. Gurugubelli, T.R.; Ravikumar, R.V.S.S.N.; Koutavarapu, R. Enhanced photocatalytic activity of ZnO–CdS composite nanostructures towards the degradation of Rhodamine B under solar Light. Catalysts.2022, 12, 84-93.
15. Dharmana, G.; Gurugubelli, T.R.; Masabattula, P.S.R.; Babu, B.; Yoo, K. Facile synthesis, characterization, and

     photocatalytic activity of hydrothermally crown Cu²⁺-doped ZnO-SnS nanocomposites for MB dye degradation.    

Catalysts.2022, 12, 328-342.

16. Alam, M.W.; Azam, H.; Khalid, N.R.; Naeem, S.; Hussain, M.K.; Baqais, A.; Farhan, M.; Souayeh, B.; Zaidi, B.; Kahan, K. Enhanced photocatalytic performance of Ag₃PO₄ /Mn-ZnO nanocomposite for the degradation of Tetracycline Hydrochloride. Crystals.2022, 12, 1156-1170.
17. El-Sayed, F.; Hussien, M.S.A.; Alabdulaal, T.H.; Ismail, A.; Zahran, H.Y.; Yahia, I.S.; Abdel-Wahab, M.S.; Khairy, Y.; Ali, T.E.; Ibrahim, M.A. Comparative degradation studies of Carmine Dye by photocatalysis and photoelectrochemical oxidation processes in the presence of Graphene/N-Doped ZnO nanostructures. Crystals.2022, 12, 535-555.
18. Landge, V.K.; Huang, C.M.; Hakke, V.S.; Sonawane, S.H.; Manickam, S.; Hsieh, M.C. Solar-energy-driven Cu-ZnO/TiO₂ nanocomposite photocatalyst for the rapid degradation of Congo Red azo dye. Catalysts.2022, 12, 605-624.

• Page 1, line 55. More introduction on the Fe2V4O13 should be added.

Ans: Thank you professor for your comment. As per the reviewer comment the references added and the manuscript was revised.

Iron tetrapolyvanadate Fe₂V₄O₁₃ has tetrahedrally coordinated VO₄ units and octahedrally coordinated Fe₂O₁₀, where VO₄ units are connected to octahedrally coordinated Fe₂O₁₀ through edge sharing, creating a unique chain structure resembling a horseshoe. It is excellent for numerous applications since it has tetrahedral and hexagonal holes and channels. For example, it has been researched as an effective cathode for lithium secondary batteries, water oxidation  photocatalyst to degrade organic pollutants , and a photocatalyst to reduce CO₂.

19. Lakkepally, S.; Kalegowda, Y.; Ganganagappa, N.; Siddaramanna, A. A new and effective approach for Fe₂V₄O₁₃ nanoparticles synthesis: evaluation of electrochemical performance as cathode for lithium secondary batteries. J. Alloys Compd. 2018, 737, 665–671.
20. Li, S.R.; Yesibolati, N.; Qiao, Y.; Ge, S.Y.; Feng, X.Y.; Zhu, J.F.; Chen, C.H. Electrostatic spray deposition of porous Fe₂V₄O₁₃ films as electrodes for Li-Ion batteries. J. Alloys Compd.2012, 520, 77–82.
21. Tang, D.; Rettie, A.J.E.; Mabayoje, O.; Wygant, B.R.; Lai, Y.; Liu, Y.; Mullins, C.B. Facile growth of porous Fe₂V₄O₁₃ films for photoelectrochemical water oxidation. J. Mater. Chem. A2016, 4, 3034–3042.
22. Muthuvel, I.; Gowthami, K.; Thirunarayanan, G.; Suppuraj, P.; Krishnakumar, B.; Sobral, A.J.F.N.; Swaminathan, M. Graphene oxide– Fe₂V₄O₁₃ hybrid material as highly efficient Hetero-Fenton catalyst for degradation of Methyl Orange. Int. J. Ind. Chem.2019, 10, 77–87.
23. Li, P.; Zhou, Y.; Li, H.; Xu, Q.; Meng, X.; Wang, X.; Xiao, M.; Zou, Z. Correction: All-Solid-State Z-Scheme System arrays of Fe₂V₄O₁₃/RGO/CdS for visible light-driving photocatalytic CO₂ reduction into renewable hydrocarbon fuel. Chem. Comm.2015, 51, 800-813.
24. Li, P.; Zhou, Y.; Tu, W.; Liu, Q.; Yan, S.; Zou, Z. Direct growth of Fe₂V₄O₁₃ nanoribbons on a stainless-steel mesh for visible-light photoreduction of CO₂ into renewable hydrocarbon fuel and degradation of gaseous isopropyl alcohol. ChemPlusChem.2013, 78, 274–278.

 

• Page 3, Fig 1. It is suggested to insert a zoom-in graph for the wavenumber < 500 part. In current format, it is very hard to view those peaks. Meanwhile, since this graph is mainly used to support “This indicates that Ag was effectively loaded on the ZnO/Fe2V4O13 nanocomposite.” (Page 2, line 85), the author should highlight more on the Ag-O. Other Zn-O and Fe-O are very as expected. There is no need to mention too much about Zn-O and Fe-O.

Ans: Thank you professor for your comment. As per the reviewer comment, the Fig 1 is modified and a zoom-in graph for the wavenumber < 500 part is given.

• Page 5, line 117. The author mentioned “EDX can generally accurately detect up to trace amount of metal”. However, for this 2 wt% sample, the inserted table in Fig 5 shows 8.5 wt%? Is this a contradiction? •

Ans: Thank you professor for your comment.

EDX can generally quantitatively detect up to trace amount of metal present on the surface of base materials. Thisanalysis is taken only aparticular area of the coated nanomaterial. Different % shows due to that particular amount of coated %.

Page 10, Fig 10. The author should explain the reason why, when Ag wt% < 2% or > 2%, the performance of (c)(d)(g) appear to be worse than without Ag (b). And overall, all cases show similar trend with overlapped curves. Therefore, it is hard to draw a conclusion with single sample. It’s better to perform multiple tests for each case and include error bar.

Ans: Thank you professor for your comment. As per the reviewer comment the Fig 10 is improved with error bar and bar diagram is inserted for easy understand.Some time, at particular level (percentage), the negative effective was also observed, and may be due to surface blocking effect.

Minor Improvement: • Page 1, line 41. Why “inefficient”? Is ZnO more effective or not, compared to TiO2?

Ans: Thank you professor for your comment. As per the previous report, the synthetic point of view, cost and UV light absorption behavior ZnO more effective than TiO₂.

11. Lee, H. J.; Kim, H.; Park, S. S.; Hong, S. S.;Lee, G. D. Degradation kinetics for photocatalytic reaction of methyl orange overAl-doped ZnO nanoparticles, J. Ind. Eng. Chem.2015, 25, 199–206.
12. Ansari, S. A.; Khan, M. M.; Ansari, M. O.; Lee, J.; Cho, M. H. Biogenic synthesis, photocatalytic, and photoelectrochemical performance of Ag–ZnO nanocomposite.J. Phys. Chem.2013, 117, 27023–27030.
13. Muñoz-Fernandez, L.; Gomez-Villalba, L.S.; Milošević, O.; Rabanal, M.E. Influence of nanoscale defects on  the improvement of photocatalytic activity of Ag/ZnO. Mater. Charact. 2022, 185, 111718-11722

. • Page 2, line 56. Given the author claimed their method is different from others, some brief introduction about previous methods should be added.

Ans: Thank you professor for your comment. As per the previous report, the encapsulation of Ag on ZnO/Fe₂V₄O₁₃ is simple, cost effective photodeposition method.

• Page 4, line 101. The author should briefly talk about how the crystallite size is calculated.

Ans: Thank you professor for your comment. As per the reviewer comment the manuscript was revised.

The Scherrer equation (eqn. 1) was employed for the calculation of the average crystallite size of 2 wt% of Ag-ZnO/Fe₂V₄O₁₃ and it is found to be 28.5 nm.

D = kl/bcosq      … (1)

Where D is the crystalline size, λ is wavelength X-ray used; K is the shape factor, b is the full width half maximum high of peak and q is the Bragg angle. This has been included in the revised manuscript.

• Page 4, line 107. Guess this is an editing issue. The author mentioned Table. 1-3, but none of them show in the manuscript or supporting information. Table 2: Page 11 line 210. Table 3: Page 13, line 255.

Ans: Thank you professor for your comment. As per the reviewer comment the manuscript has been revised.

• Page 4, Fig 2. The author should explain why Fe2V4O13 peaks (in Fig 2b) don’t show in (c)-(f).

Ans: Thank you professor for your comment. The relative concentration of Fe₂V₄O₁₃ is very low as compared to ZnO in the nanocomposite. Since the Fe₂V₄O₁₃ peaks are not obtained in XRD pattern. As per the reviewer comment the manuscript has been revised.

• Page 6, Fig 4(d). There are two numbers (11.72 nm and 13.10 nm) in the image. What are they?

Ans: Thank you professor for your comment. These are approximate particle size given from the instrument.

• Page 8, Fig 7(d). The author showed a 0.2 nm layer on the particle, but didn’t say what it is. Is this the Ag coating layer?

Ans: Thank you professor for your comment. The lattice spacing of 0.2 nm is for (101) planes of wurtzite ZnO. Text revised.

• Page 11, line 189. The author should define “photodegradation and decolorization”. It seems photodegradation means 80% reduction, decolorization means 100%.

Ans: Thank you professor for your comment. Photodecolorization is the cleavage of azo bond ie removal of colour( bleaching)(n to Л*).Photodegradation is the breakdown of organic part of the dye molecule (Л to Л*). Usually photodecolourization process is much faster than photodegradation.

• In SI, Page 6. It is interesting to see excessive catalyst will suppress the degradation. The author is suggested to explain it.

Ans: Thank you professor for your comment.

Further increase of catalyst amount (above 3 g L^–1) decreases the removal efficiency. Enhancement of removal efficiency is due to the following reasons: i) the dosage of catalyst increases the amount of dye adsorbed on the surface of catalyst, ii) the area of illumination may also increase. The decrease in efficiency of MO at higher dosage (above 3 g L^-1) may be due to light scattering effect by the catalyst. The optimum amount of catalyst for efficient degradation of MO is 3 g L^–1. Text revised in supporting material.

• Page 11, Fig 11. This figure can be further improved. For example, rescaling y axis to between 80% - 100%.

Ans: Thank you professor for your comment. As per the reviewer comment the Fig 11 is improved with error bar and rescaled.

 

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

All my comments and suggested revisions were correctly taken into account by the author. I think that the manuscript can now be published in its present form. 

 

Comments for author File: Comments.docx

Author Response

Comments and Suggestions for Authors.

All my comments and suggested revisions were correctly taken into account by the author. I think that the manuscript can now be published in its present form. .

Ans: Thank you for your comment. We would like to thank you for your prompt consideration of our manuscript.

Reviewer 2 Report

Thanks the author for revising this work. It has great improvement and resolved all comments properly. 

Author Response

Comments and Suggestions for Authors

Thanks the author for revising this work. It has great improvement and resolved all comments properly. 

Ans: Thank you for your comment. We would like to thank you for your prompt consideration of our manuscript.