A Novel SnO₂/ZnFe₂O₄ Magnetic Photocatalyst with Excellent Photocatalytic Performance in Rhodamine B Removal

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The study of magnetic photocatalysts, namely SnO2/ZnFe2O4 could be of interest to the scientific community. However, the novelty from other, similar works (for instance –DOI: 10.1016/j.matchemphys.2021.124273 or DOI: 10.1007/s10854-022-08879-2) should be better highlighted.

The following remarks were observed:

·       Title should be revised: either “Novel SnO2/ZnFe2O4 magnetic photocatalysts” or “A novel SnO2/ZnFe2O4 magnetic photocatalyst” to match singular/plural nouns with the nominatives

·       Fig1 is informative, although the quality (resolution) should be improved

·       chapter 2.2. has a important deficiency: all relevant measurement conditions and parameters must be reported! Not only the name/type of applied equipment.

·       chapter 2.3. The spectral radiance must be disclosed. Xe-lamp has components in the hard UV-region as well - it contradicts the "simulated sunlight" conditions mentioned in chapter 3.1. Please elaborate or amend!

·       chapter 3.1. the use of Rhodamine B should be better explained as a test compound. There is a widespread use of it in the literature, however, the use of (fluorescent) dyes can be questionable, as the change in the fluorescent (intensity) change is related to the chromophore groups, which not necessarily indicate structural degradation (can be sensitive to H change as well). Please consider and elaborate. It is recommended to supplement the pH values along with the data, or use TOC determination.

·       Fig. 2/a. Please explain the efficiency decrease (min 0) then increase (min 30) of sample ZFO upon irradiation.

·       Chapter 3.2. Is the presence of individual SnO2 and ZFO crystallites are beneficial, or the modified crystal structure (e.g. enhanced presence of heterojunctions) are considered better? It would be beneficial to compare with literature results.

·       Chapter 3.2., Figure 5. not all of the EDX peaks are assigned, however it is claimed that “no impurity elements present”. Please add the measurement conditions, as Cu lines are probably present due to the sample carrier.

·       Figure 5/a-d should be completely revised. Distribution are not visible, it is not informative in current format. Contrast might be uniformly increased, or data collection parameters fine tuned. How was the signal processed? Almost all results (Figure 5/d especially) seems like noise.
Also, SEM images must be attached for the elemental maps to identify the area of analysis! An overlap with the original (visual) image and the maps are recommended.

·       Figure 6/d: fitting should be revised, decomposition clearly does not fit the observed curve. R2 values, or other similar parameters should be expressed for the fitting. Also, the line coloring (green, orange) should be explained in Figure caption.

·       lines 184-185:  please clarify if elemental (metal, Sn⁰) or ionic (Sn⁴⁺) form is identified, or their dual presence is to be expected.

·       chapter 3.4. The use of SI units are recommended or at least the density should be given so that the Readers can do the transformation.

·       chapter 3.5. Please support the usability of scavenger compounds in the photocatalysis measurement with literature. Also, please properly describe experimental conditions, as dissolved oxygen could significantly influence Benzoquinone determination and lead to inaccurate determinations (for instance: DOI: 10.1016/j.jphotochem.2020.113057).

Comments on the Quality of English Language

Minor revision of English is recommended.

Author Response

Review 1#:

The study of magnetic photocatalysts, namely SnO₂/ZnFe₂O₄ could be of interest to the scientific community. However, the novelty from other, similar works (for instance –DOI: 10.1016/j.matchemphys.2021.124273 or DOI: 10.1007/s10854-022-08879-2) should be better highlighted.

 

The following remarks were observed:

1. The title should be revised: either “Novel SnO₂/ZnFe₂O₄ magnetic photocatalysts” or “A novel SnO₂/ZnFe₂O₄ magnetic photocatalyst” to match singular/plural nouns with the nominatives.

Reply: Thanks for pointing this out. We have revised the original title to “A novel SnO₂/ZnFe₂O₄ magnetic photocatalyst……”.

 

2. Fig1 is informative, although the quality (resolution) should be improved.

Reply: Thanks for your significant advice, the origin Fig. 1 has been replaced to more higher quality images.

 

3. chapter 2.2. has a important deficiency: all relevant measurement conditions and parameters must be reported! Not only the name/type of applied equipment.

Reply: Thank you for your significant reminder. We appreciate your proposal and have revised the Structural Characterization section accordingly. The specific change is shown in section 3.2, page 13.

 

4. chapter 2.3. The spectral radiance must be disclosed. Xe-lamp has components in the hard UV-region as well - it contradicts the "simulated sunlight" conditions mentioned in chapter 3.1. Please elaborate or amend!

Reply: Thanks for pointing this out. We have revised the description in the chapter 2.1.

 

5. chapter 3.1. the use of Rhodamine B should be better explained as a test compound. There is a widespread use of it in the literature, however, the use of (fluorescent) dyes can be questionable, as the change in the fluorescent (intensity) change is related to the chromophore groups, which not necessarily indicate structural degradation (can be sensitive to H change as well). Please consider and elaborate. It is recommended to supplement the pH values along with the data, or use TOC determination.

Reply: Thank you for your valuable comments on the manuscript. The authors highly agree with you. We have completed the TOC determination. The results displayed that the removal efficiency of SnO₂, ZFO, and SZ-5 for RhB were 54.7%, 32.5%, and 63.1%, respectively, which confirmed the RhB molecule has been effectively degraded, and the composite catalyst significantly improved the catalytic performance compared with the single samples.

 

6. Fig. 2/a. Please explain the efficiency decrease (min 0) then increase (min 30) of sample ZFO upon irradiation. Chapter 3.2. Is the presence of individual SnO₂ and ZFO crystallites are beneficial, or the modified crystal structure (e.g. enhanced presence of heterojunctions) are considered better? It would be beneficial to compare with literature results.

Reply: Thank you for your careful review of this point. The photocatalytic degradation efficiency of the pure phase ZFO had a certain decrease after the completion of the dark reaction. This decrease might be attributed to the RhB adsorbed in the dark reaction stage being desorbed in the photocatalytic reaction stage. According to the previous studies ¹ and our previous research ², the performance of single SnO₂, ZFO crystallite, and physical mixture SnO₂ and other catalysts were not as good as that observed for the heterojunction SnO₂/other catalysts, which further indicated the heterojunction helped to improve the catalytic performance, and the performance was higher than that of a single sample.

 

7. Chapter 3.2., Figure 5. not all of the EDX peaks are assigned, however, it is claimed that “no impurity elements present”. Please add the measurement conditions, as Cu lines are probably present due to the sample carrier.

Reply: Thanks for your valuable suggestion. We are very sorry for the incorrect statement and revised it in the manuscript. We have added the measurement conditions in section 3.2.

 

8. Figure 5/a-d should be completely revised. Distribution are not visible, it is not informative in the current format. The contrast might be uniformly increased, or data collection parameters fine-tuned. How was the signal processed? Almost all results (Figure 5/d especially) seem like noise. Also, SEM images must be attached for the elemental maps to identify the area of analysis! An overlap with the original (visual) image and the maps are recommended.

Reply: Thanks for your valuable comments. The EDS has been re-tested, and the results show the O, Fe Sn, and Zn elements were uniformly distributed on the surface. We also added the original (visual) image SEM in the EDS spectrum.

9. Figure 6/d: fitting should be revised, decomposition clearly does not fit the observed curve. R² values, or other similar parameters should be expressed for the fitting. Also, the line coloring (green, orange) should be explained in Figure caption.

Reply: Thanks for your valuable comment. We refitted the problematic elements and added the specific descriptions and discussions in red font in the manuscript. R² value has been added to the Figure, and the lines in the figure are explained.

 

10. lines 184-185:  please clarify if elemental (metal, Sn⁰) or ionic (Sn⁴⁺) form is identified, or their dual presence is to be expected.

Reply: Thanks for pointing this out. The Sn can be attributed to the Sn⁴⁺ valence state, which is consistent with the previous research ³.

 

11. chapter 3.4. The use of SI units are recommended or at least the density should be given so that the Readers can do the transformation.

Reply: Thanks for your available comments. We use the emu/g as the magnetization unit, which is the same as the previous studies of magnetic photocatalysts ^{2, 4 5 6}. We think maybe using emu/g as the magnetization unit in photocatalysts is a well-founded choice that aligns with established practices in the field, facilitating a better understanding of the magnetic properties of photocatalysts.

 

12. chapter 3.5. Please support the usability of scavenger compounds in the photocatalysis measurement with literature. Also, please properly describe experimental conditions, as dissolved oxygen could significantly influence Benzoquinone determination and lead to inaccurate determinations (for instance: DOI: 10.1016/j.jphotochem.2020.113057).

Reply: Thank you so much for your reminder. We have added the literature as the reference for the selection of the trapping agent, which was shown on lines 258-259 of the manuscript. We are very sorry we did not specifically emphasize the experimental conditions in the capture process. We have added the experimental conditions with details in section 3.3. The additive amounts of IPA and TEOA were 1 mM each, while the amount of BQ was only 0.01 mM (ensuring there was no excess BQ that could be consumed with electrons). Combined with the degradation results of the free radical capture experiment (Fig. 12), this demonstrated that ·O₂^- played a major role in the photocatalysis process. Hoping our response is satisfactory to reviewers and agree to publish this manuscript.

References

 

1. Assis, G. C.; Silva, I. M. A.; Dos Santos, T. V.; Meneghetti, M. R.; Meneghetti, S. M. P., Photocatalytic properties of SnO2/MoO3 mixed oxides and their relation to the electronic properties and surface acidity. Journal of Photochemistry and Photobiology A: Chemistry 2021, 407.
2. Xie, T.; Xu, L.; Liu, C.; Wang, Y., Magnetic composite ZnFe2O4/SrFe12O19: Preparation, characterization, and photocatalytic activity under visible light. Applied Surface Science 2013, 273, 684-691.
3. Shuaishuai, J.; Wan, X.; Cuimin, Z.; Feihu, L.; Bo, M.; Zili, Z., Improving the formaldehyde gas sensing performance of the ZnO/SnO₂ nanoparticles by PdO decoration. Journal of Materials Science: Materials in Electronics 2019, 31, (1), 684-692.
4. Elanthamilan, E.; Elizabeth, I. B.; Wang, S. F.; Lydia, I. S., Strontium hexaferrite microspheres: Synthesis, characterization and visible-light-driven photocatalytic activity towards the degradation of methylene blue dye. Optical Materials 2023, 137.
5. Xu, S. H.; Feng, D. L.; Li, D. X.; Shangguan, W. F., Preparation of magnetic photocatalyst TiO₂ supported on NiFe₂O₄ and effect of magnetic carrier on photocatalytic activity. Chinese Journal of Chemistry 2008, 26, (5), 842-846.
6. Han, M. J.; Wang, S. F.; Yu, X. M.; Yu, X. L.; Gao, H. J.; Zhou, X. J.; Li, D. F.; Fang, L. M.; Angadi, V. J.; Ubaidullah, M.; Pandit, B., A novel CuAl2O4/MoS₂/BaFe₁₂O₁₉ magnetic photocatalyst simultaneously coupling type I and Z-scheme heterojunctions for the sunlight-driven removal of tetracycline hydrochloride. Environmental Science-Nano 2024.

 

 

 

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

The paper by Hao et al deals with a study of ZnFe2O4-SnO2 systems for dye photodegradation. Results of photocatalytic degradation of RhB and characterization of selected systems are used to establish structure/activity relationships. Main concern with this study is the fact that the photoactivity of most active system SZ-5 appears close to that of ZFO-free SnO2 (Fig. 2 in the ms.). Additionally, the specific surface area of the former is higher than that of the latter suggesting a higher surface activity of the latter. In contrast, a clear activity decrease is observed for samples with 3, 7, and 10 % ZFO. On the whole it does not remain clear what the role, further than magnetic recovery of the sample, of the ZFO component is. The characterization of mentioned less active SZ-3 -7, and/or -10 samples is expected in that sense while adequate discussion is missing. Photocatalytic experiments employing visible light lamps or filters are expected in order to analyse differences and establishing more clearly the role of ZFO, if any role at all. The XPS results are poorly described, interpreted and discussed. Fittings do not appear correct while programs are widely available.  Different contributions appear at least in O1s and Fe2p zones which should be adequately described and discussed. 

Comments on the Quality of English Language

Some editing required.

Author Response

The paper by Hao et al deals with a study of ZnFe2O4-SnO2 systems for dye photodegradation. Results of photocatalytic degradation of RhB and characterization of selected systems are used to establish structure/activity relationships. Main concern with this study is the fact that the photoactivity of most active system SZ-5 appears close to that of ZFO-free SnO₂ (Fig. 2 in the ms.). Additionally, the specific surface area of the former is higher than that of the latter suggesting a higher surface activity of the latter. In contrast, a clear activity decrease is observed for samples with 3, 7, and 10 % ZFO. On the whole it does not remain clear what the role, further than magnetic recovery of the sample, of the ZFO component is. The characterization of mentioned less active SZ-3 -7, and/or -10 samples is expected in that sense while adequate discussion is missing. Photocatalytic experiments employing visible light lamps or filters are expected in order to analyse differences and establishing more clearly the role of ZFO, if any role at all. The XPS results are poorly described, interpreted and discussed. Fittings do not appear correct while programs are widely available.  Different contributions appear at least in O 1s and Fe 2p zones which should be adequately described and discussed. 

 

Response: Thanks for your valuable suggestion. The composite ratio significantly influences the performance of SnO₂-ZnFe₂O₄ (ZFO) photocatalysts due to the critical role of interfacial interactions. At lower ZFO mass ratios (3% and 5%), the interfacial effects may be insufficient, hindering the efficient formation of heterojunctions, which are essential for enhancing photocatalytic activity [1]. This insufficient interaction results in decreased photocatalytic efficiency because the necessary synergistic effects between SnO₂ and ZFO are not fully realized [2]. Conversely, a higher ZFO mass ratio (10%) can lead to two main drawbacks. First, excessive ZFO coverage on SnO₂ can block active sites on its surface, impeding the photoexcitation process and thereby reducing overall photocatalytic activity [3]. Second, a higher ZFO content means a lower relative amount of SnO₂, which possesses stronger intrinsic photocatalytic properties. This imbalance results in a decreased ability to generate photogenerated carriers effectively [4]. Therefore, the optimal photocatalytic performance of the SnO₂-ZFO composite is achieved at an appropriate mass ratio, specifically around 5%. At this ratio, the best interfacial effects, optimal energy band structure modulation, and effective distribution of surface reaction active sites can be achieved, leading to maximal photocatalytic efficiency [4].

We also measure the photocatalytic activity under the visible light condition, which displays the same trend with Xe-lamp irradiation. Compared with SnO₂ (62.7%), the photocatalytic efficiency of the composite sample (79.7%) was significantly improved. It further confirms the importance of ZFO and supports the point we made above.

Also, the high-resolution energy spectra of O 1s and Fe 2p have been re-evaluated, and additional explanations and discussions concerning these elements have been incorporated to provide a more comprehensive understanding of their roles in the photocatalytic process, as mentioned in lines 167-177 of the revised manuscript. Hoping our response is satisfactory to reviewers and agree to publish this manuscript.

 

References

 

1. Guo, L. F.; Okinaka, N.; Zhang, L. H.; Watanabe, S., Facile synthesis of ZnFe₂O₄/SnO₂ composites for efficient photocatalytic degradation of methylene blue. Mater. Chem. Phys. 2021, 262, 7.
2. Liu, X. Y.; Shu, J. H.; Wang, H. Y.; Jiang, Z.; Xu, L. J.; Liu, C. L., One-pot preparation of a novel CoWO4/ZnWO4 p-n heterojunction photocatalyst for enhanced photocatalytic activity under visible light irradiation. J. Phys. Chem. Solids 2023, 172, 8.
3. Jiang, Z.; Hao, Y.; Wu, T. Z.; Xu, L. J.; Liu, C. L.; Liu, X. Y., Carbon-coated Mn x Zn 1-x Fe 2 O 4 as a magnetic substrate for Zn 0.8 Cd 0.2 S applied in photocatalytic rhodamine B. Opt. Mater. 2021, 112, 9.
4. Zhang, D. F.; Zhang, R. Q.; Jiang, X.; Zhang, D.; Li, H. S.; Liu, J. C.; Pu, X. P.; Cai, P. Q., A novel SnIn4S8/ZnFe2O4 S-scheme heterojunction with excellent magnetic properties and photocatalytic degradation activity for tetracycline. Dalton Trans. 2023, 52, (41), 14956-14966.

 

Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

In the paper entitled "A novel SnO₂/ZnFe₂O₄ magnetic photocatalysts with excellent photocatalytic performance", Hao and co-workers fabricated a new type of photocatalytic material, which was characterized and utilized in the photodegradation of rhodamine B. The obtained results are worth publishing in Catalysts. However, a major revision ought to be performed before publication due to several issues:

1.    Line 86 – no verb in this sentence. Please correct.

2.    Lines 93-95 – “…and the reaction vessel was allowed to stand for 24 hours. The reaction vessel was then allowed to stand for 30 minutes.” – So it was allowed to stand for 24 hours or 30 min? Please rewrite this for clarity.

3.    Results and Discussion – at the beginning, please add a small paragraph regarding the formulation of the photocatalyst and put Fig.1 below this description.

4.    What was the absorption rate after 30 min of incubation of RhB with photocatalyst before light irradiation?

5.    Have the authors measured the actual loading of ZnFe₂O₄ on the surface of SnO₂? The provided EDS measurements are insufficient, as they are not accurate.

6.    Photocatalytic studies – according to the UV-VIS DRS measurements, the optimal light irradiation should cover only the UV range. In the photocatalytic studies, the xenon lamp was used to imitate sunlight. To evaluate the photocatalytic activity of the obtained material, the studies should be repeated, at least in the case of SZ-5, using a UV light source only

7.    UV-VIS DRS studies – The edge wavelength of 362.9 nm doesn’t mean this is a visible spectrum range. Please correct it. Moreover, please provide the UV-VIS DRS spectra of all obtained photocatalysts to prove and discuss the influence of ZFO loading on the edge wavelength.

8.    What about recycling and reusability of the obtained photocatalyst? Have the authors performed some additional cycles of irradiation with the material recollected?

9.    The obtained results of the photocatalytic studies should be compared with the literature data (preferably in the form of a table) to assess the activity of the obtained material in the photodegradation of RhB against the background of others.

Comments on the Quality of English Language

Line 86 – no verb in this sentence. Please correct.

Author Response

1. Line 86 – no verb in this sentence. Please correct.

Respond: We appreciate your valuable comments on this point. We have corrected this sentence in the revised manuscript and highlighted it in red in line 303.

 

2. Lines 93-95 – “…and the reaction vessel was allowed to stand for 24 hours. The reaction vessel was then allowed to stand for 30 minutes.” – So it was allowed to stand for 24 hours or 30 min? Please rewrite this for clarity.

Respond: We are very grateful for your valuable suggestions. This passage had redundant statements added due to our writing errors, which we have removed in the manuscript. The redescription is shown in lines 316-318.

 

3. Results and Discussion – at the beginning, please add a small paragraph regarding the formulation of the photocatalyst and put Fig.1 below this description.

Respond: We are very grateful for your suggestions on the point. Following your comments, we have added a small description of the preparation of the series of photocatalysts at the corresponding positions in the revised manuscript (lines 78-79) and changed the position of Figure 1.

 

4. What was the absorption rate after 30 min of incubation of RhB with photocatalyst before light irradiation?

Respond: We sincerely thank the reviewer for careful reading. As shown in Fig. 2(a), the absorption of RhB before the light was 8.6% and 21.3% for single samples SnO₂ and ZnFe₂O₄, and 9.2%, 5.1%, 3.7%, and 4.2% for composite samples SZ-3, SZ-5, SZ-7, and SZ-10, respectively. We also added the absorption rate in the manuscript.

 

5. Have the authors measured the actual loading of ZnFe₂O₄ on the surface of SnO₂? The provided EDS measurements are insufficient, as they are not accurate.

Respond: Thank you for your significant reminder. When preparing the composite photocatalyst SZ-5, according to the mass ratio of ZnFe₂O₄ to SnO₂ of 5:100, a certain amount of ZnFe₂O₄ was added to the composite photocatalyst, and the theoretical atomic percentages of Zn and Fe were 1.2% and 2.1%, respectively, and the atomic percentage of Zn was almost the same as that of the result of 0.9% obtained from the EDS, but the atomic percentage of Fe in the EDS test result was reduced since Fe was easily adsorbed in the reactor liner in the hydrothermal process, so we did not measure the actual loading amount of ZnFe₂O₄ on the surface of tin dioxide. However, due to the decrease of Fe content during the hydrothermal process due to the easy adsorption of Fe in the reactor liner, the atomic percentage of Fe in the EDS test result was reduced, so we did not measure the actual loading of ZnFe₂O₄ on the surface of tin dioxide, but we found that the purity of the SZ-5 samples was higher by combining it with the results of the EDS test. In future studies, we will conduct more accurate quantitative tests to further confirm the loading of ZnFe₂O₄ on the surface of SnO₂.

 

6. Photocatalytic studies – according to the UV-VIS DRS measurements, the optimal light irradiation should cover only the UV range. In the photocatalytic studies, the xenon lamp was used to imitate sunlight. To evaluate the photocatalytic activity of the obtained material, the studies should be repeated, at least in the case of SZ-5, using a UV light source only.

Respond: Thank you point out this. The xenon lamp used in the photocatalytic degradation experiments contained a small amount of UV light, we also determined the photocatalytic activity under visible light conditions, the results as shown in the following figures, which displayed the almost same trend with Xe-lamp irradiation. Hence, in the UV light irradiation, the SZ-5 may obtain better photocatalytic activity, because the UV light has the more higher energy.

7. UV-VIS DRS studies – The edge wavelength of 362.9 nm doesn’t mean this is a visible spectrum range. Please correct it. Moreover, please provide the UV-VIS DRS spectra of all obtained photocatalysts to prove and discuss the influence of ZFO loading on the edge wavelength.

Respond: We appreciate your valuable feedback and we have removed the incorrect statement in the revised version. Meanwhile, the UV-VIS DRS curves show that the composite SZ-5 has a higher absorption wavelength length in the visible range compared to SnO₂ and lower than the ZFO single sample, which is precisely due to the strong interaction between ZnFe₂O₄ and SnO₂ leading to the enhancement of the absorption wavelength intensity. Since the results of the optimum composite sample SZ-5 as well as the single sample are mainly discussed in this paper, the UV-visible diffuse reflectance spectra of the other scaled composite samples not be analyzed for the time being for the sake of uniformity. Also, according to the results, e.g. photocatalytic efficiency, the ZFO loading too much or too little might cause the absorption wavelength length to shorten compared with SZ-5.

 

8. What about recycling and reusability of the obtained photocatalyst? Have the authors performed some additional cycles of irradiation with the material recollected?

Respond: We are very grateful for your valuable comments on this point. According to your comments, we have carried out recycling experiments on the optimal composite sample SZ-5 (as shown in the following Figure), and the photocatalytic degradation effect of the composite photocatalysts after four runs did not change significantly, and could still reach more than 67%, which indicates that the SnO₂/ZnFe₂O₄ composite magnetic photocatalysts have excellent stability and reusable value.

9. The obtained results of the photocatalytic studies should be compared with the literature data (preferably in the form of a table) to assess the activity of the obtained material in the photodegradation of RhB against the background of others.

Respond: Thanks for your valuable counsel. Comparisons with other studies are presented in Table 1, from which it can be seen that the composite magnetic photocatalysts prepared in this study performed better than the previously reported photocatalysts. Hoping our response is satisfactory to reviewers and agree to publish this manuscript.

 

Author Response File: Author Response.docx

Reviewer 4 Report

Comments and Suggestions for Authors

The research has a good scope. The modification of the catalyst and the influence of the synthesis method are demonstrated. The analytical techniques used support the results. The UV spectroscopy technique is not suitable to demonstrate the reduction in the concentration of the rhodamine molecule (they do not use a calibration curve) it was best to use HPLC or another technique. There is no quality control in UV measurements. In different journals, UV measurements are not acceptable, because there is a high probability of reporting erroneous results.

"A new SnO2/ZnFe2O4 magnetic photocatalyst with excellent 

Photocatalytic performance in (molecule) removal".

Author Response

The research has a good scope. The modification of the catalyst and the influence of the synthesis method are demonstrated. The analytical techniques used support the results. The UV spectroscopy technique is not suitable to demonstrate the reduction in the concentration of the rhodamine molecule (they do not use a calibration curve) it was best to use HPLC or another technique. There is no quality control in UV measurements. In different journals, UV measurements are not acceptable, because there is a high probability of reporting erroneous results.

"A new SnO₂/ZnFe₂O₄ magnetic photocatalyst with excellent Photocatalytic performance in (molecule) removal".

Reply: We are very grateful for your suggestions. We also determined the TOC value of the RhB. The results displayed that the removal efficiency of SnO₂, ZFO, and SZ-5 for RhB were 54.7%, 32.5%, and 63.1%, respectively, which demonstrated the organic or molecule removal of the RhB. For future research, we plan to conduct HPLC experiments to further investigate the changes in the molecular structure of RhB. Hoping our response is satisfactory to reviewers and agree to publish this manuscript.

 

Author Response File: Author Response.docx

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

Dear Authors,

All my issues have been addressed. I have no further comments. The manuscript can be published in its present form.