Synthesis, Crystal Structure, and Electrochemical Properties of an Isopolyoxovanadate Compound Modified Transition-Metal Complex Based on [V4O12]4−
Round 1
Reviewer 1 Report
Attached are the comments.
Comments for author File: 
Comments.pdf
Author Response
For Reviewer 1
- Authors presented/wrote both abstract and the conclusion part almost same. They simply wrote the conclusion part as abstract. Both abstract and the conclusion parts should not be same.
Response: Thanks for your valuable comments. We have rewritten the conclusion in the revised manuscript.
- 2. Reference format is inconsistent throughout the paper. For example, some of the journals abbreviations were used and in some, full journal name was used.
Response: Thank you very much for your advice. We have checked the reference carefully and all the formats have been revised to be consistent.
- References 37 and 38 are same. Sheldrick, G.M. SHELXL−97, Program for Crystal Structure Refinement, University of Göttingen, Göttingen, Germany, 1997.
Response: Thank you very much for pointing out my mistake. We have already deleted one of them.
- Reference articles titles format is consistent. Either capitalize each letter in a word or just use same style for all the references. There are many other errors, they all need to be corrected.
Response: Thank you very much for pointing out my mistake, all the errors have been revised in the reference.
- Lines 24-26 needs to be rewritten
Response: Thank you very much for your advice. We have checked the manuscript carefully and rewritten.
“…… POMs possess large number of negative with unique chemical composition and structural diversity, which can be considered to be one of the ideal candidates for electrocatalyst [5]. ……”
- 6. Figure S4. FTIR spectrum has many absorption peaks, so authors should clearly mention or give some symbols to figure out easily. It is hard to find the peaks.
Response: We feel great thanks for your professional review work on our article, we have identified absorption peaks in the infrared spectrum and the new spectrum has been placed in SI.
Fig. S4. FT-IR spectrum of compound 1.
- 7. 5. The cyclic voltammograms of the CPE-1 in H2SO4 aqueous solution has an arrow mark (may be showing down), another arrow mark?
Response: Thank you for your careful reading of our manuscript. We have added a upward arrow mark in Fig. 5 and arrow up or down represent the increase of DA and AA concentration.
Fig. 5. The cyclic voltammograms of the CPE-1 in H2SO4 aqueous solution (0.1 mol×L-1) containing DA (left) and AA (right), scan rate: 100 mV·s−1 (the arrow up or down represent the increase of DA and AA concentration from inner to outer: 0, 20, 40, 60, 80 and 100 mM)
- 8. Include the amount of triethylenetetramine and acetic acid were used to adjust the pH.
Response: Thank you for your instructive suggestions. We have added the amount of triethylenetetramine and acetic acid in “synthesis, Line 221-223”.
“......The pH value of the resulting solution was adjusted to 10.5 using approximately 0.35 mL of triethylenetetramine and then added 0.3 mL acetic acid to adjust pH to be 7.0......”
- 9. The π-π interactions of compound 1, between the Zn complexes and phen are not same. So how phen helps to stabilize the compound 1
Response: Thanks for your comment. We've already explained how phen helps stabilize one-dimensional structure in “Characterization of compound 1, Line 76-78”.
“......In the crystal structure, between the phen (N7, N8) from Zn(2)-phen unit and free phen (N13, N14) are also exit π-π stacking interaction, which makes the one-dimensional structure more stable......”.
Reviewer 2 Report
In this manuscript, the authors reported synthesis, characterization, and electrochemical properties of an isopolyoxovanadate containing Zn metal. Authors explained the structural properties of the newly designed vanadate using XRD, IR, UV-vis spectroscopy, and showed its nature in detecting some useful chemicals such as dopamine and ascorbic acid. However, the detail experimental observation and results do not meet the standard of the journal Catalysts. After careful reviewing of the manuscript and for the best interests of our readers, it is recommended to publish the manuscript elsewhere.
Here is a useful feedback to the authors to consider:
In the electrochemical catalysis, there is not enough evidence or justification of how well the catalysts perform compared to industry standard. Also, there is significant improvement needed in the article in order to detect the overall stability of the electrocatalyst. Explanation of why DA signals are higher than AA is also missing in the explanation. Was there is any experiments performed to study the chronoamperometry of the catalysis mentioned? Finally, any comment on the potential mechanistic path for the catalysis and its final products would also add value to the articles.
Author Response
For Reviewer 2
- In the electrochemical catalysis, there is not enough evidence or justification of how well the catalysts perform compared to industry standard.
Response: We feel great thanks for your professional review work on our article. As far as I know, there are no relevant methods for DA and AA catalysis in industry standards. Whereas, literature search indicates that this is the first [V4O12]4--based compound reported for the study of electrocatalytic properties and we will continue to expand electrochemical properties.
- Also, there is significant improvement needed in the article in order to detect the overall stability of the electrocatalyst.
Response: Thanks a lot for your advice. According to your nice suggestions, we have carried out the stability of the electrocatalyst in H2SO4 aqueous solution containing 20 mM AA by cyclic voltammetry. And the revised parts were added in line 155-158”
Fig. S8. Cyclic voltammograms of compound 1 in H2SO4 aqueous solution containing 20 mM AA after 100 consecutive cycles.
- Explanation of why DA signals are higher than AA is also missing in the explanation.
Response: Thank you for your suggestion. We have explained why the signals of DA is higher than AA in line 152-154 of the revised manuscript.
“......That may be because the ester group in the structure of ascorbic acid has an attractive effect on electrons, resulting in the hindrance of electron transfer during the reaction process......”
- Was there is any experiments performed to study the chronoamperometry of the catalysis mentioned?
Response: We failed to provide satisfactory study result for the chronoamperometry after trying several times. But the dopamine detection has been investigated by differential pulse voltammetry method. Differential pulse voltammetry (DPV) method can obtain stronger signal by eliminating the non-Faradaic currents that occur with CV and has better sensitivity for the detection of small biomolecules. With the increase of substrate concentration, the oxidation peak currents will respond quickly and sensitively, which is consistent with the chronoamperometry.
- Finally, any comment on the potential mechanistic path for the catalysis and its final products would also add value to the articles.
Response: Thank you for your instructive suggestion, we have added the potential mechanistic path and final products of DA and AA in line 141-143 of the revised manuscript.
Scheme 1: Electron transfer process of DA and AA
Author Response File: Author Response.pdf
Reviewer 3 Report
In their manuscript, the authors have synthesized a new isopolyoxovanadate compound phen = 1,10- 10 phenathroline) and characterized the obtained material using different techniques.
After reviewing the article, some of the comments are given below:
-The indexation of XRD and IR spectra should be done
-What was the used electrolyte in the electrochemical measurements, add it to the materilas part
-Figures 4 and 5 X axis, add the reference used (V vs...)
-Figure 4, the anodic region is hidden
-Morphological characterization must be carried out
-As no catalytic reactions were carried out, authors are invited to develop the part of dopamine detection
Author Response
For Reviewer 3
- 1. The indexation of XRD and IR spectra should be done.
Response: Thanks for your advice. Since the [V4O12]4- anions are obtained from commercially purchased chemicals, we could not obtain powder X-ray diffraction patterns directly. However, the XRD of phen has been tested and identified in the manuscript and IR spectra has been identified in support information.
Fig. S3. The powder X-ray diffraction patterns calculated from the single-crystal data (top), obtained from the experiments (middle) for 1 and phen (bottom).( blue dots: absorption peaks of [V4O12]4- anions and red star: absorption peaks of phen)
Fig. S4. FT-IR spectrum of compound 1.
- What was the used electrolyte in the electrochemical measurements, add it to the materilas part
Response: Thank you for your careful reading of our manuscript. We have added the used electrolyte in the electrochemical measurements in line 215.
“......The pH value of the resulting solution was adjusted to 10.5 using approximately 0.35 mL of triethylenetetramine and then added 0.3 mL acetic acid to adjust pH to be 7.0.......”
- Figures 4 and 5 X axis, add the reference used (V vs...)
Response: Thank you very much for your advice. We have modified axis 4 and 5 axis.
- Figure 4, the anodic region is hidden
Response: We are very sorry for our mistake, and we have changed the X-axis range.
Fig. 4. The cyclic voltammograms of the CPE-1 in H2SO4 aqueous solution (0.1 mol×L-1) at different scan rates (from inner to outer: 20, 40, 60, 80, 100, 120, 140 and 160, 180, 200 mV·s−1)
- 5. Morphological characterization must be carried out
Response: Thank you for the suggestion. Based on your advice, we investigated the morphological by SEM and observed that compound 1 exhibited a smooth rhomboid crystal.
Fig. S6. Scanning electron microscopy of compound 1.
- 6. As no catalytic reactions were carried out, authors are invited to develop the part of dopamine detection.
Response: Thanks for your valuable comments. According to the suggestion, the dopamine detection have been carried out by differential pulse voltammetry method, and the relative part were added in line 159-170
Fig. 6. Differential pulse voltammograms of 1-modified GCE in H2SO4 aqueous solution (0.1 molL-1) with increasing concentrations of DA from 0.002 to 50 mM. Insets: linear relations of DPV peak currents for 1-modified GCE with the increasing of DA.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Thank you for responding with proper justification and experimental evidence for all the questions and concerns raised in the first round of revision.
Reviewer 3 Report
The authors have answered the comments properly, therefore, the revised manuscript can be accepted for publication.
