Carbonization of Zr-Loaded Thiourea-Functionalized Styrene-Divinylbenzene Copolymers: An Easy Way to Synthesize Nano-ZrO2@C and Nano-(ZrC, ZrO2)@C Composites
, Zoltán Károly 1, Laura Bereczki 1, László Trif 1, Attila Farkas 3, Alfréd Menyhárd 2 and László Kótai 1,4,*
Round 1
Reviewer 1 Report
The work of L. Kótai et al. is devoted to the synthesis of nano-ZrO2@C and nano-(ZrC, ZrO2)@C composites by carbonization of Zr-loaded thiourea-functionalized styrene-divinylbenzene copolymers. The work is a meticulously executed study: each stage of the process was studied in detail using a wide range of experimental methods, such as FT-IR, XPS, TG-MS, etc. The authors demonstrated the effect of carbonization conditions on the composition and properties of the resulting composites. The work can be accepted for publication after taking into account the following minor remark:
The Figure 1 represents the FT-IR spectra only in 800–600 and 1700–1500 cm-1 ranges while in the text vibrations at 1000–870, 1110, 1420 cm-1 are discussed. The full range FT-IR spectra can be found in ESI, but, in my opinion, it is better to put it in main text for reader's convenience. Also, the vibration band at 700cm-1 is highligted by dashed line in the figure, but not discussed in the text. is it neccisary to higlight this band?
Author Response
First of all, We would like to express our many thanks to the reviewer for their efforts to improve our manuscript.
The work of L. Kótai et al. is devoted to the synthesis of nano-ZrO2@C and nano-(ZrC, ZrO2)@C composites by carbonization of Zr-loaded thiourea-functionalized styrene-divinylbenzene copolymers. The work is a meticulously executed study: each stage of the process was studied in detail using a wide range of experimental methods, such as FT-IR, XPS, TG-MS, etc. The authors demonstrated the effect of carbonization conditions on the composition and properties of the resulting composites. The work can be accepted for publication after taking into account the following minor remark:
The Figure 1 represents the FT-IR spectra only in 800–600 and 1700–1500 cm-1 ranges while in the text vibrations at 1000–870, 1110, 1420 cm-1 are discussed. The full range FT-IR spectra can be found in ESI, but, in my opinion, it is better to put it in main text for reader's convenience. Also, the vibration band at 700cm-1 is highligted by dashed line in the figure, but not discussed in the text. is it neccisary to higlight this band?
These have been revised according to the reviewer’s request.
Reviewer 2 Report
Thiourea-functionalized resin was Zr-loaded and carbonized to form ZrO2@C and (ZrC, ZrO2)@C composites, which structure was thoroughly investigated in the manuscript “Carbonization of Zr-loaded thiourea-functionalized styrene-divinylbenzene copolymers: an easy way to synthesize nano-ZrO2@C and nano-(ZrC, ZrO2)@C composites” (ID: jcs-2503513). The experiments are quite detailed; however, their discussion should be significantly improved throughout the revision.
General comment:
1) Please consider some unification of the sample titles: in Table 2, sample is indicated as “R_1000C_2h_P_Ar-He”, in Fig. S5 (ESI), “R_P_Ar-He”, in Fig. S4 (ESI), “Resinex_Plasma Ar-He”. The precursor is named “Resinex CH-80-L” in line 64 and “R_RAW” in Fig. 5; while in ESI Table 1, apparently, the Zr-loaded sample is named “Resinex-Cl”, and these notations are only used once and not defined. Other notations, such as “R_1000C-2h”, are understandable, but they are also not defined in the text explicitly, which hinders the understandability of the figures. Please revise the notations.
2) Currently, the assessment of the presented figures may be hindered by people with poor eyesight. Consider increasing the thickness of the lines and axes, and the size of font.
Detailed comments:
3) Lines 58-59, please kindly point out what studies suggest that “The distribution of zirconium in the functional groups is homogeneous at the atomic level.”
4) Line 69, define “DVB”.
5) Lines 140-146, what was the excitation laser power?
6) Lines 149-156, what calibration of the XPS spectrometer was used?
7) Line 153, define “PE”.
8) Please communicate on how and where was the heat flow (ESI Fig. 2, right scale) measured, and why μV are its measurement units.
9) In the scheme 1 or its caption, please clarify what process/reaction is represented by arrow.
10) In the footnote to the Table S1, what do you mean by “m/m”?
11) Line 193, it is unclear why the fragment “NH2 deformation band at 1604 cm-1” is bracketed. Is NH2 band somehow connected to the H2O-related line?
12) Line 202, what do you mean be “condensed Zr-O bond”? Did you mean “Zr-O in condensed phase”?
13) Lines 201-202: discussed 870-1000 cm-1 region is not visible in the Fig. 1. Consider adjusting the X scale break to show it or state in the text that the peak is not detected.
14) In Fig. 2 and 3, black line is related to the left scale, and dashed lines are related to right scale? Please communicate it in the figure and/or its caption.
15) In Fig. 3a, not all of the dashed black line is visible. Consider adjusting the scale of the left Y axis.
16) Lines 273-275, please point out what studies suggest the following: “ZrC formed only at 1400 °C in 8 h, whereas ZrO2 was created at all three studied temperatures. Tetragonal and monoclinic ZrO2 were detected at 1000 °C, embedded in graphite and amorphous carbon.” Are these results presented in the paper?
17) In Table 1, fix the typo “ZrO2 content ans size” in the 1st row.
18) Please communicate on the origin of the data presented in Table 1: what analyses were carried out, was HRTEM used to assess the statistics of ZrO2/ZrC inclusions, or were their sizes determined by XRD? I think, the placement of this table and related discussions after the presentation of TEM studies (after Fig. 5) would be more logically correct.
19) Table 2: please discuss why the particular kinds of treatment (1400C-8h and 1000C-2h-P-Ar-He) lead to such a prominent development of the structure.
20) In the legend of ESI Figure 4 (Raman spectra), I suggest to present the origin of the lines rather than indicate them as “Fit peak N”.
21) Line 331, did you mean “Table 3”?
22) Section “Raman studies on ZrO2@C and (ZrC,ZrO2)@C composites”: I understand why plasma treatment leads to the formation of “superficial (subsurface) graphene layers”; however, why do you emphasize that predominantly “surface graphene layers” exist in the annealed sample? Why do you suppose that there is no graphene in the volume of the structure?
23) Line 343: “The more ZrC is formed, the more graphite appears.” According to Table 1, that is not the case, as R_1400C-2h sample has a largest amount of graphite and no ZrC. Please clarify what did you mean by this sentence.
24) Line 353, “The spectra contain satellites and confirm the aromatic nature of the carbon phases”: did you mean that the positioning of the satellite at 6-7 eV is typical for pi-plasmon, which is characteristic for sp2-hybridized phase [https://doi.org/10.1016/j.tsf.2021.138993]? Consider supplementing the discussion.
25) Lines 355-356, “No Zr-compounds were detected at the surface layer”: how was this data obtained? Did you mean that Zr3d peak was not observed in the survey spectra. Then, why are the spectra not shown and/or the elemental composition of the sample is not derived?
26) Table 3, is the “RF plasma, He” line related to current study? Does it report on the “R_1000C_2h_P_Ar-He” or “R_P_Ar-He” sample? Consider supplementing the information regarding the thermal annealing of the sample and/or the Ar presence in the work gas atmosphere throughout the plasma treatment.
27) Fig. S5 (ESI) is not referenced in the text.
28) Line 383, fix the typo in “ZrO2@”.
Some typos and wording issues are underlined in the "Comments and Suggestions for Authors" (comment 11, 17, 28). Overall, English is understandable.
Author Response
First of all, We would like to express our many thanks to the reviewer for their efforts to improve our manuscript.
Thiourea-functionalized resin was Zr-loaded and carbonized to form ZrO2@C and (ZrC, ZrO2)@C composites, which structure was thoroughly investigated in the manuscript “Carbonization of Zr-loaded thiourea-functionalized styrene-divinylbenzene copolymers: an easy way to synthesize nano-ZrO2@C and nano-(ZrC, ZrO2)@C composites” (ID: jcs-2503513). The experiments are quite detailed; however, their discussion should be significantly improved throughout the revision.
General comment:
- Please consider some unification of the sample titles: in Table 2, sample is indicated as “R_1000C_2h_P_Ar-He”, in Fig. S5 (ESI), “R_P_Ar-He”, in Fig. S4 (ESI), “Resinex_Plasma Ar-He”. The precursor is named “Resinex CH-80-L” in line 64 and “R_RAW” in Fig. 5; while in ESI Table 1, apparently, the Zr-loaded sample is named “Resinex-Cl”, and these notations are only used once and not defined. Other notations, such as “R_1000C-2h”, are understandable, but they are also not defined in the text explicitly, which hinders the understandability of the figures. Please revise the notations.
These revisions have been done.
2) Currently, the assessment of the presented figures may be hindered by people with poor eyesight. Consider increasing the thickness of the lines and axes, and the size of font.
We did our best to improve the figure’s quality.
Detailed comments:
3) Lines 58-59, please kindly point out what studies suggest that “The distribution of zirconium in the functional groups is homogeneous at the atomic level.”
Since the functional groups are located homogeneously and regularly in the STY-DVB skeleton, and the zirconium is bound to them only, the distribution of zirconium is also homogeneous due to the nature of ion exchange.
4) Line 69, define “DVB”.
It has been given (divinylbenzene).
5) Lines 140-146, what was the excitation laser power?
It has been introduced.
6) Lines 149-156, what calibration of the XPS spectrometer was used?
Linearity of the BE scale was checked using silver. Graphitic carbon line located at 284.5 eV was used for the BE calibration of the spectra.
7) Line 153, define “PE”.
It has been given (photoelectron)
8) Please communicate on how and where was the heat flow (ESI Fig. 2, right scale) measured, and why μV are its measurement units.
It is mW. The instrument measures potential difference, which is adjusted to convert that into mW. It is our fault not to mark that it has been converted to mW.
9) In the scheme 1 or its caption, please clarify what process/reaction is represented by arrow.
The thiourea functionalization process is given. The caption has been modified according to this.
10) In the footnote to the Table S1, what do you mean by “m/m”?
mass/mass, (wt. %). It has been revised.
11) Line 193, it is unclear why the fragment “NH2 deformation band at 1604 cm-1” is bracketed. Is NH2 band somehow connected to the H2O-related line?
Yes, they partly covered. The sentence has been revised.
12) Line 202, what do you mean be “condensed Zr-O bond”? Did you mean “Zr-O in condensed phase”?
Zirconyl ion can be condensed into a framework-like structural units (e.g. Zr4(OH)8(H2O)16](8+)) (line 180). The text has been modified.
13) Lines 201-202: discussed 870-1000 cm-1 region is not visible in the Fig. 1. Consider adjusting the X scale break to show it or state in the text that the peak is not detected.
The complete IR spectrum has been introduced.
14) In Fig. 2 and 3, black line is related to the left scale, and dashed lines are related to right scale? Please communicate it in the figure and/or its caption.
It has been done.
15) In Fig. 3a, not all of the dashed black line is visible. Consider adjusting the scale of the left Y axis.
We did our best to improve it.
16) Lines 273-275, please point out what studies suggest the following: “ZrC formed only at 1400 °C in 8 h, whereas ZrO2 was created at all three studied temperatures. Tetragonal and monoclinic ZrO2 were detected at 1000 °C, embedded in graphite and amorphous carbon.” Are these results presented in the paper?
The results written in lines 273-275 refer to the current study and are obtained by powder XRD analysis. The results are also presented in Table 1 and ESI Figure S5.
17) In Table 1, fix the typo “ZrO2 content ans size” in the 1st row.
It has been revised.
18) Please communicate on the origin of the data presented in Table 1: what analyses were carried out, was HRTEM used to assess the statistics of ZrO2/ZrC inclusions, or were their sizes determined by XRD? I think, the placement of this table and related discussions after the presentation of TEM studies (after Fig. 5) would be more logically correct.
The sizes were determined by XRD. TEM measurements gives information about several aprticles, the XRD relates to the average of the bulk. It has been introduced.
19) Table 2: please discuss why the particular kinds of treatment (1400C-8h and 1000C-2h-P-Ar-He) lead to such a prominent development of the structure.
The text has been revised. “The increase in the specific surface area may be attributed to the formation of ZrC (1400 °C/8h and 1000 °C/2h-P-Ar-He samples) as a result of the ZrO2 and carbon reaction due to the breaking of the carbon network and forming new surfaces”.
20) In the legend of ESI Figure 4 (Raman spectra), I suggest to present the origin of the lines rather than indicate them as “Fit peak N”.
A curve fitting procedure was used to check completeness of the fitting of the measured and calculated ones.
21) Line 331, did you mean “Table 3”?
Yes, thank you. It has been revised.
22) Section “Raman studies on ZrO2@C and (ZrC,ZrO2)@C composites”: I understand why plasma treatment leads to the formation of “superficial (subsurface) graphene layers”; however, why do you emphasize that predominantly “surface graphene layers” exist in the annealed sample? Why do you suppose that there is no graphene in the volume of the structure?
The Raman characteristics found refer to subsurface graphene layers.
23) Line 343: “The more ZrC is formed, the more graphite appears.” According to Table 1, that is not the case, as R_1400C-2h sample has a largest amount of graphite and no ZrC. Please clarify what did you mean by this sentence.
It has been revised.
24) Line 353, “The spectra contain satellites and confirm the aromatic nature of the carbon phases”: did you mean that the positioning of the satellite at 6-7 eV is typical for pi-plasmon, which is characteristic for sp2-hybridized phase [https://doi.org/10.1016/j.tsf.2021.138993]? Consider supplementing the discussion.
The C 1s spectrum of graphitic carbon is characterized by an asymmetric peak shape and π-π* shake-up satellite line. See reference David J. Morgan Journal Of Carbon Research 2021, 7, 51.
25) Lines 355-356, “No Zr-compounds were detected at the surface layer”: how was this data obtained? Did you mean that Zr3d peak was not observed in the survey spectra. Then, why are the spectra not shown and/or the elemental composition of the sample is not derived?
The Zr spectra have been inserted.
26) Table 3, is the “RF plasma, He” line related to current study? Does it report on the “R_1000C_2h_P_Ar-He” or “R_P_Ar-He” sample? Consider supplementing the information regarding the thermal annealing of the sample and/or the Ar presence in the work gas atmosphere throughout the plasma treatment.
In Table 3 there are several “RF plasma, He” lines. The listed data in a particular line were obtained in the paper referred to the last column. The two lines without any reference but an asterisk are related indeed to the current study. To prevent any misunderstandings, we give a comment about it in the footnote.
27) Fig. S5 (ESI) is not referenced in the text.
It has been at line 381.
28) Line 383, fix the typo in “ZrO2@”.
It has been revised.
Round 2
Reviewer 1 Report
The authors edited the manuscript in accordance with the reviewer's comments. The article may be published in its current form.
Author Response
Thank you.
Reviewer 2 Report
Revised version of the manuscript jcs-2503513 “Carbonization of Zr-loaded thiourea-functionalized styrene-divinylbenzene copolymers: an easy way to synthesize nano-ZrO2@C and nano-(ZrC, ZrO2)@C composites” has resolved most of the technical issues of the manuscript. However, most of somewhat in-depth problems still remain and need to be addressed.
Major comment:
1) The reply to Comment 18 didn’t allow me and readers to understand what studies revealed the carbon content in wt.% and allowed authors to distinguish graphite from amorphous carbon.
2) Comment 25 was answered incompletely. Why are the survey XPS spectra of the samples not shown and/or the elemental compositions of the samples are not derived from survey XPS? Currently, the subsurface layers of the material are being analyzed only by C1s fitting (Fig. 6), and C=O lines emergence for the (c) and (d) subfigures is not discussed at all. As C-O and C-N lines can emerge in similar region, discussion of the elemental composition would allow authors to present more detailed analysis of the subsurface region of the material.
Minor comments:
3) The revision related to the general comment 1 still has a room for improvement, as notations used by authors (such as 1000 °C/2h) have not been defined in the text.
4) Comment 8 was not resolved: In “Materials and methods” section please provide the details of the heat flow measurement, which results are provided in ESI Fig. S1, right scale.
5) In the ESI Figure S5, axes titles and tick labels are not visible, please revise.
6) Raman analysis depth for graphitic materials is tenths of nanometers (40-50 nm, according to [10.1016/j.jnucmat.2007.05.040] and refs. 17-18 within). Therefore, the suggestion that Raman revealed the information about “surface graphene layers” (line 344) is, in my opinion, incorrect. Please revise.
7) The revision related to Comment 20 haven’t been made. In ESI Figure S3, please indicate the origin of the peaks rather than indicating them as “Fit Peak X”.
8) FTIR spectra presented in Fig. 1 are not informative. Please indicate the origin of the discussed lines.
9) Lines 195-197, please indicate the positions of the H2O-related bands and provide appropriate references. By “OH-stretching band”, did you mean the line located at 3400 cm-1 [10.3390/jcs7040156, 10.3390/jcs7070264]?
10) Line 359, the sentence “The spectra contain satellites and confirm the aromatic nature of the carbon phases.” should discuss the origin of the satellites and elaborate on the suggested conclusion. Please indicate that pi-pi* transitions/pi-plasmon losses emerge only in sp2-hybridized carbon, which confirms your suggestion.
11) Lines 356-364: please provide appropriate references indicating that C-C and C=O lines are positioned in the suggested region.
Author Response
Thank you for your valuable comments and critical remarks. We have now corrected our original manuscript. All changes are highlighted for convenience. I think there were some misunderstandings earlier regarding some issues but we do hope that the changes we have made will fully satisfy your expectations.
Revised version of the manuscript jcs-2503513 “Carbonization of Zr-loaded thiourea-functionalized styrene-divinylbenzene copolymers: an easy way to synthesize nano-ZrO2@C and nano-(ZrC, ZrO2)@C composites” has resolved most of the technical issues of the manuscript. However, most of somewhat in-depth problems still remain and need to be addressed.
Major comment:
- The reply to Comment 18 didn’t allow me and readers to understand what studies revealed the carbon content in wt.% and allowed authors to distinguish graphite from amorphous carbon.
Comment 18 contained a question related to the size determination not the ratio of amorphous carbon/graphite. We gave that we used the Scherrer equation to determine the size of crystallites (ZrO2, ZrC). Although the reviewer suggested moving Table 1 after the TEM studies, however, it would decompose the logic of the paper completely. Regarding the new question, the crystalline components distribution (in wt. %) was determined by PXRD as was given in the text. The Raman measurements gave information about the amorphous carbon/graphite ratio (it is an estimated ratio, of course, not an analytical determination), and when amorphous and crystalline carbon (graphite) were present together, we corrected the overall carbon content contents according to this. The ratio of amorphous/graphitic carbon would be estimated by PXRD as well, but to evaluate the very wide “hill” of amorphous components and compare that with sharp peaks of crystalline components, similar amorphous/crystalline standards should have been used, or a good model for the structure of the amorphous carbon. Therefore, we used the abovementioned approximation and estimation. It has been given in the text now.
2) Comment 25 was answered incompletely. Why are the survey XPS spectra of the samples not shown and/or the elemental compositions of the samples are not derived from survey XPS? Currently, the subsurface layers of the material are being analyzed only by C1s fitting (Fig. 6), and C=O lines emergence for the (c) and (d) subfigures is not discussed at all. As C-O and C-N lines can emerge in similar region, discussion of the elemental composition would allow authors to present more detailed analysis of the subsurface region of the material.
Thank you for the improving remarks of the referee.
We think that showing the survey spectra would not be very informative. Zirconium is under the detection limit by XPS on the surface of all investigated samples. That means that on the basis of IMFP calculations, the outer carbon layer has a minimal 6 nm thickness.
We’ve remade the XPS analysis of the carbon spectra using AS(70;0,7) asymmetric peak shape for the graphite (instead of the original AS(40;0,6)) as it is described for graphite samples in reference [M. Fronczak, A. M. Keszler, M. Mohai, B. Jezsó, A. Farkas, Z. Károly Carbon 193 (2022) 51-67.]. The carbon 1s XPS spectra in the case of the plasma-treated samples can be well fitted only by adding oxidized carbon peaks and we added the oxidized carbon peaks in the case of the heat-treated samples as well to determine their possible amount in all samples. Using the new AS(70;0,7) peak shape, the amount of the oxidized carbon species slightly increased. In our second analysis, we used two types of oxidized carbon lines to make the analysis more exact. We used epoxy carbon lines at 286.6 eV and carbonyl lines at 287.6 eV BE. The presence of oxidized carbon species is also supported by the oxygen detected by XPS. Nitrogen could not be detected on the surfaces and that’s why C-N compounds are not discussed in the text. The results of the elemental analysis are shown in the table in atomic %:
|
O |
Cgraphite |
C-O-C |
C=O |
|
6,3 |
85,5 |
3,3 |
4,8 |
|
5,1 |
88,0 |
4,3 |
2,7 |
|
3,2 |
94,5 |
1,0 |
1,3 |
|
2,0 |
95,0 |
1,5 |
1,5 |
Minor comments:
- The revision related to the general comment 1 still has a room for improvement, as notations used by authors (such as 1000 °C/2h) have not been defined in the text.
It has been done.
- Comment 8 was not resolved: In “Materials and methods” section please provide the details of the heat flow measurement, which results are provided in ESI Fig. S1, right scale.
We have done our best already to explain it. We can repeat that only. The instrument measured microV. The software (after adjusting) converts it into mW. The measured values were converted into mW, but erroneously, our coworker who made the figures gave the originally measured unit (microV) instead of the converted value unit (mW).
- In the ESI Figure S5, axes titles and tick labels are not visible, please revise.
It has been revised.
6) Raman analysis depth for graphitic materials is tenths of nanometers (40-50 nm, according to [10.1016/j.jnucmat.2007.05.040] and refs. 17-18 within). Therefore, the suggestion that Raman revealed the information about “surface graphene layers” (line 344) is, in my opinion, incorrect. Please revise.
It has been revised.
7) The revision related to Comment 20 haven’t been made. In ESI Figure S3, please indicate the origin of the peaks rather than indicating them as “Fit Peak X”.
Originally we did not do it because the positions were given, and everybody could assign each component. However, because the reviewer insists on it, we put the assignations of each peak.
8) FTIR spectra presented in Fig. 1 are not informative. Please indicate the origin of the discussed lines.
The fingerprint region has no novelty because that was discussed many times for DVB-styrene copolymers. The sole purpose we performed and showed the IR measurement to decide whether the OH bands belong to water or hydroxide ions. That has been discussed. Some remarks about IR, according to the reviewer’s request, are inserted into the text. The type of OH bands (hydroxide or water) is the one important thing, that has been discussed in detail by using the scissoring mode of water.
9) Lines 195-197, please indicate the positions of the H2O-related bands and provide appropriate references. By “OH-stretching band”, did you mean the line located at 3400 cm-1 [10.3390/jcs7040156, 10.3390/jcs7070264]?
The bands of water are trivial enough. In addition, even if I were to provide references, it would not have much meaning because the thiourea NH2 bands are in hydrogen bonds with water and shift these overlapping stretching bands seriously. Only a wide band is observed consisting of many modes belonging to many groups. A similar situation is with thioamide and water deformation modes.
10) Line 359, the sentence “The spectra contain satellites and confirm the aromatic nature of the carbon phases.” should discuss the origin of the satellites and elaborate on the suggested conclusion. Please indicate that pi-pi* transitions/pi-plasmon losses emerge only in sp2-hybridized carbon, which confirms your suggestion.
We inserted explanation to that part: The spectra contain π-π* shake-up satellites, which confirm the aromatic nature of the carbon phases that in our case refers for a graphite phase.
11) Lines 356-364: please provide appropriate references indicating that C-C and C=O lines are positioned in the suggested region.
We added references, as follows: For the position of the C=O lines, the following reference was given: I. Bertóti, M. Mohai, K. László Carbon 84 (2015) 185-196. For the C-C lines, David J. Morgan Journal Of Carbon Research (2021), 7, 51 reference was given.
Round 3
Reviewer 2 Report
Authors of “Carbonization of Zr-loaded thiourea-functionalized styrene-divinylbenzene copolymers: an easy way to synthesize nano-ZrO2@C and nano-(ZrC, ZrO2)@C composites” (ID: jcs-2503513) have addressed most of the manuscript’s issues. However, in the reply authors have stated that “The Raman measurements gave information about the amorphous carbon/graphite ratio (it is an estimated ratio, of course, not an analytical determination), and when amorphous and crystalline carbon (graphite) were present together, we corrected the overall carbon content contents according to this.” The estimation of the graphitic to a-C ratio via Raman spectroscopy is unconventional, and I suggest it to be described in more detail. Was the graphite to a-C ratio assessed as the ratio of 1580 cm-1 to 1500 cm-1-centered lines? Was the relation of the areas or intensities of the peaks evaluated? Was polyynic contribution taken into account?
Additionally, I have noticed that current version of the Abstract is 263 words long, however, according to journals’ guidelines [https://www.mdpi.com/journal/jcs/instructions], the abstract should be a total of about 200 words maximum. Please revise.
