Ultra-Trace Monitoring of Methylene Blue Degradation via AgNW-Based SERS: Toward Sustainable Advanced Oxidation Water Treatment

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

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Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

After reviewing the paper titled “Monitoring Methylene Blue Degradation by Coaxial DBD Plasma and TiO₂ Nanotube Photocatalysis via AgNW-Enhanced SERS”. This study presents a very sensitive and reproducible detection approach for environmental applications based on AgNW-based SERS, with the potential for further development and wider application. The following comments are provided for the authors' consideration and revision:

• There is a need for a few small grammar corrections, especially in the parts that describe the experimental setup.
• The introduction clearly states the need for more sensitive detection methods; however, it may benefit from a brief discussion of the limitations of current SERS-based approaches in comparison to other methods such as electrochemical sensors or immunosensors
• Include the diameter and length distributions of the nanowires, as these can influence the enhancement factor.
• Calibration curves (Figure 5b) and the chosen Raman peak (~1626 cm⁻¹) could be used to better understand the impact of different laser powers on reproducibility and signal saturation.
• Comparing the results to other nanostructures (e.g., Ag nanospheres or hollow nanostructures) may provide more context for the superiority of AgNWs in this application.
• Fluorescence quenching occurs at greater concentrations and may cause interference at intermediate levels (10⁻⁷ M to 10⁻⁴ M). Why?
• There is no mention of temperature control during the measurements. Because Raman scattering is temperature-dependent, including this element could help in comprehending potential signal changes.
• The discussion of degradation processes is restricted. Understanding the intermediates generated during MB degradation can provide insight into the success of applied approaches (e.g., TiO₂ nanotubes and DBD plasma).
• The paper does not address the long-term durability of AgNW-based substrates, which is critical for practical applications. The durability of the AgNW substrates in repeated measurements or under hostile environmental conditions is not assessed.
• There is no cost comparison of the AgNW-based SERS technology to simpler, traditional methods such as UV-Vis or fluorescence spectroscopy, which would be useful in determining the possibility for general use.
• The experimental set-up is complicated. Sophisticated techniques, such as UV-Vis spectroscopy, fluorescence, and SERS, are combined with complex degradation processes like DBD plasma and TiO₂ photocatalysis. This multi-technique approach may limit the method's applicability to real-world applications where simpler or less expensive ways could be applied.
• The authors should explain how environmental conditions (such as humidity and temperature) may influence hotspot formation.
• Please provide R² values for both linear and non-linear fitting.

 

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

1. In order to maintain the scientific integrity, the proper publicationsconcentrated on the SERS-based dye degradation monitor should be summarized for highlighting your novelty in “introduction”. 
2. There is no enough comparison data. How about selecting other noble metal (e., Au) SERS for MB monitor?
3. Yourdiscussion related to mechanism is not clear, it is better to confirm the dominate reactive species (i.e., quenching experiment and ESR) and degradation pathway (i.e., LC-MS and TOC).
4. According to your result, how about the global optimization of TiO₂with respect to DBD Plasma for overall catalytic enhancement?
5. Having gone through the paper, I just considered that the origin of dye-sensitized TiO₂may be happened. It is better to provide the additive data for uncovering the detailed charge injection or transfer.
6. From the consideration of practical application, how about the continuous reusability? The structural characterizations after reusability arerequired to confirm their structural stability.

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

In this paper, the application of surface-enhanced Raman spectroscopy (SERS) platform based on silver nanowires (AgNW) in methylene blue (MB) degradation monitoring was investigated. Combined with titanium dioxide nanotube (TiNT) photocatalysis and dielectric barrier discharge (DBD) plasma treatment, SERS showed significant advantages in ultra-low concentration detection. The research and design system with detailed data provides a new perspective for environmental pollutant monitoring. The current manuscript has been written well and understandable and is recommended to be accepted for publication in this journal with minor revision requested as follows:

1. The negative sign (−) in the figure is incorrectly marked and should be distinguished from the hyphen (-).
2. It is recommended to combine (a) and (b) of Figure 5 on one page.The image format is not uniform. For example, a) and (a) are mixed. 
3. In the field of SERS detection of MB, there have been many studies using nanostructured materials for detection. In order to make the study more comprehensive and in-depth, it is suggested to add a comparison with other materials in terms of sensitivity and detection range.
4. Although the mechanism of MB degradation is discussed, the possible reactions and intermediates involved are mentioned, further analysis is lacking. Can more experimental data or theoretical calculations be combined to determine the specific structure and transformation path of intermediate products, so as to enhance the depth of research and its scientific rigor?
5. It seems that the reference S1 in the Supplementary Material is provided incorrectly, since the corresponding reference cannot be found according to the provided DOI, and it also seems that the title is wrong. Besides, reference S2 is not in the same format as other references and does not provide the DOI.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

No

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have addressed my comments, and the manuscript is clearly improved.