Study of the Iodine Fixation over High Surface Area Graphite (HSAG-100) Under Mild Conditions

Round 1

Reviewer 1 Report

Dear Authors,
the topic of the work is interesting and current. You have shown a lot of results, but I would like to make some remarks and suggestions.

Does the commercial material that you used and stated that it is a specific area (SBET = 100 m2/g) belong to a large area as you said?
and on what basis did you conclude that?
Why did you use commercial ones and not make the material yourself?
Have you confirmed that (100 m2/g)
Separate the experimental from the method
You don't need the formula or put it in an additional material with some other things
Picture 1. Why didn't you mark anything in the picture?
Why didn't you give the distribution of pores and isotherms?
Picture 2 b) there are a lot of sums, sort it out
In picture 7, you didn't mark the peaks?
Why didn't you show SEM and EDS?
Also FTIR
Technically organize the work.
Analyzing the results step by step, it seems as if everything has been thrown away
Specify a specific application?
Put recent references, not older than 5 years

Dear Authors,
the topic of the work is interesting and current. You have shown a lot of results, but I would like to make some remarks and suggestions.

Does the commercial material that you used and stated that it is a specific area (SBET = 100 m2/g) belong to a large area as you said?
and on what basis did you conclude that?
Why did you use commercial ones and not make the material yourself?
Have you confirmed that (100 m2/g)
Separate the experimental from the method
You don't need the formula or put it in an additional material with some other things
Picture 1. Why didn't you mark anything in the picture?
Why didn't you give the distribution of pores and isotherms?
Picture 2 b) there are a lot of sums, sort it out
In picture 7, you didn't mark the peaks?
Why didn't you show SEM and EDS?
Also FTIR
Technically organize the work.
Analyzing the results step by step, it seems as if everything has been thrown away
Specify a specific application?
Put recent references, not older than 5 years

Author Response

We are pleased to submit the revised version of the manuscript “Study of the iodine fixation over high surface area graphite (HSAG-100) under mild conditions” to be reconsidered for its publication in Reactions.

We are grateful for the thoughtful and constructive comments. We have substantially revised the manuscript to improve clarity, organization, and technical completeness. The suggested changes have significantly improved the manuscript.

 

 

Does the commercial material that you used and stated that it is a specific area (SBET = 100 m2/g) belong to a large area as you said? and on what basis did you conclude that?

Response: We used a commercial high-surface-area graphite (TIMREX® HSAG-100, IMERYS), an industry denomination that identifies this graphite family. Our own N₂ physisorption at 77 K gave S_BET = 88 ± 2 m² g⁻¹, with a type-IV isotherm (H3 loop) and BJH mesopore mode ~3.3–3.5 nm, consistent with the HSAG-100 grade and literature values. Hence, our “high-surface-area” descriptor follows both supplier classification and our measurements. See Section 2.1 Materials, Figure 4, and Table 1 in the manuscript.

 

Why did you use commercial ones and not make the material yourself?

Response: Our study isolates the iodination under mild, scalable conditions as the scientific variable. Using a well-defined commercial HSAG minimizes batch-to-batch variability and enhances reproducibility and comparability across laboratories. The text now clarifies this rationale in Section 1 (Introduction) and Section 2.1 (Materials).

 

Have you confirmed that (100 m2/g)

Response: Yes—see our independent N₂ physisorption data: S_BET = 88 ± 2 m² g⁻¹ for the parent HSAG (degas 493 K, 10 h). Isotherm shape and PSD are shown in Figure 4, values summarized in Table 1. These numbers are in line with HSAG-100 specifications and prior reports.

 

Separate the experimental from the method

Response: We have reorganized Section 2 into clearly labeled subsections: 2.1 Materials (sources/specs), 2.2 Iodination procedures (synthetic steps, timing, temperatures), and 2.3 Characterization methods (instrumentation and data-reduction protocols). This separation was implemented throughout the revised text.

 

You don't need the formula or put it in an additional material with some other things

Response: The requested formula and ancillary details have been removed from the main text

 

Picture 1. Why didn't you mark anything in the picture?

Response: Figure 1 (XPS survey) is now annotated with labels/arrows indicating the relevant core levels (C 1s, O 1s, I 3d, K 2p, Fe peaks). The caption specifies acquisition parameters and the elements detected per sample.

 

Why didn't you give the distribution of pores and isotherms?

Response: We now provide both the N₂ adsorption–desorption isotherm and the BJH pore-size distribution for the parent HSAG in Figure 4, and report the textural metrics for all samples in Table 1. The mesoporous character (type-IV, H3 loop) and a broad PSD centered at ~3.5 nm are explicitly shown.

 

Picture 2 b) there are a lot of sums, sort it out

Response: The I 3d XPS deconvolutions (Figure 2b) have been simplified: we now display only the physically justified components (I 3d₅/₂ and I 3d₃/₂ doublet) with standard area/position constraints. The panel layout/legends have been clarified for readability.

 

In picture 7, you didn't mark the peaks?

Response: Figure 7 (XRD) now includes indexed markers for graphitic reflections, with the (002) at ~26.5° 2θ and d₀₀₂ ≈ 0.334 nm indicated in the caption. This also highlights the absence of any (002) shift upon iodination (i.e., no intercalation).

 

Why didn't you show SEM and EDS?

Response: Our mechanistic conclusions rely on surface-sensitive probes (XPS, LEIS) plus textural/structural methods (BET, TGA/TPD, XRD). For lamellar graphite, SEM mainly confirms morphology (unchanged here), while EDS—being comparatively bulk and with limited surface sensitivity—adds little beyond elemental presence already established by XPS/LEIS. We state this explicitly in the Discussion; (Current evidence: XPS I 3d at ~620.3 eV consistent with C–I, LEIS signal at ~1800 eV confirms iodine in the outermost layer.)

 

Also FTIR

Response: For graphitic carbons, FTIR bands associated with C–I on edge sites are weak/broad and often masked by the strong graphitic background; thus FTIR is not diagnostic here. Instead, we use XPS to identify C–I (I 3d₅/₂ ~620.3 eV, distinct from K–I at ~619.1 eV) and TGA/TPD to demonstrate thermal stability/absence of physisorbed iodine. These data sets directly support covalent C–I formation and are presented in Figure 2, Figure 5–6, with assignments discussed in Section 3–4.

 

Technically organize the work.

Response: The manuscript has been restructured as follows: concise Introduction (context and objective), fully separated Section 2 (materials, synthesis, methods), sequential Results (XPS/LEIS → BET/PSD → TGA/TPD → XRD), an integrative Discussion that triangulates evidence toward edge-site C–I formation (no intercalation), and Conclusions. Figure captions were expanded,

 

Analyzing the results step by step, it seems as if everything has been thrown away

Response: We now guide the reader step-wise: (i) XPS/LEIS confirm iodine presence and localization at the outermost surface; (ii) BET/PSD show moderate S_BET decrease with preserved mesoporosity; (iii) TGA/TPD exclude physisorbed iodine and reveal high-T stability; (iv) XRD shows unchanged (002), ruling out laminar intercalation. The Discussion (Section 4) synthesizes these orthogonal data into a coherent mechanism—covalent C–I at edge sites—and explicitly states the logic chain.

 

Specify a specific application?

Response: The revised Introduction states our target context: alkaline-resistant, metal-free carbons for aqueous-phase processes. Iodinated HSAG provides polarizable C–I edge functionalities that can act as electronic/acidic modifiers and as anchoring motifs, making these materials promising supports/catalysts in base-rich media and platforms for sensing/adsorption in water (as discussed with recent halogen-doped carbon applications cited therein). We have added this focus explicitly and reiterated it in the Conclusions.

 

Put recent references, not older than 5 years

Response: We updated the bibliography with multiple recent works (2024–2025) on halogen-doped carbons and related functionalities, which are now cited in the Introduction (e.g., 2024–2025 Chem. Eng. J., Mater. Today Quantum, Diamond & Related Materials, etc.)

 

We trust that these clarifications and the modifications incorporated into the revised manuscript address the reviewer’s concerns and contribute to improving the overall quality and clarity of the work.

Reviewer 2 Report

The manuscript can be accepted only after major revision with providing additional information.

Reviewer report on manuscript carbon-3786688

1. Maroto-Valiente et al. “Study of the iodine fixation over high surface area graphite (HSAG-100) under mild conditions”

 

In the present study, the incorporation of iodine into the structure of high surface area graphite (HSAG) under mild conditions and with green solvents was studied. The efficiency in iodine fixation has been verified by XPS, LEIS, TGA, TPD, BET and XRD.

 

The manuscript can be accepted only after major revision with providing additional information.

Below, I point out several questions to help the authors improve the manuscript before publication.

Questions/comments:

1. The English should be improved to more clearly express the research. In some sentences, some words are missing, so it’s not possible to understand the meaning of the sentence Generally accepted scientific terminology should be corrected.
2. The manuscript is poorly formatted. The figures are hard to read. Most of the references are not up to date.
3. Abstract is not meaningful and should be re-written.
4. The introduction doesn’t provide sufficient background and doesn’t include all relevant references. Therefore, it should be extended. Some important up-to-date investigations in this field are missing and should be added, e.g. about bromine doped graphene [Nanomaterials, 2022, 12(1), 45], and references there.
5. As Authors mentioned on page 2: “Carbon nanotubes (CNTs) [1], carbon nanofibers (CNFs) [2], graphite[3], and graphene-like[4] structures attract intense research interest…“ Some novel carbon nanomaterials are missing and should be added, e.g. carbyne [Polymer Degradation and Stability, 2022, 203, 110054], graphynes [Belenkov et al. chapter “Graphynes: Advanced carbon materials with layered structure” in book “Handbook on the Graphene”, Zhang (Ed.) Wiley-Scrivener, 2019 (DOI: 10.1002/9781119468455.ch42)], and references there.
6. More details to the section “2. Experimental methods” should be added, including information about X-ray photoelectron spectra collecting. The energy resolution and pass energy values during X-ray photoelectron spectra acquisition should be written. The procedures for X-ray photoelectron spectra calibration should be well-described. The procedure for compensation of material charging should be described. The procedure for spectra deconvolution should be well described.
7. Some words are missing in sentences: “In HSAG sample pristine only C and =(2.5at.%) is de-tected. HSAG treated samples registered iodine, larger in those prepared in decane with (IKFeD) and without iron (IKD) (~0.6 - 0.7 at%) than in those prepared in water with (IKFeW) and without iron (IKW) (~0.05 - 0.1%at).“ (page 3). It should be corrected.
8. Figure 1 is not meaningful. It should be edited and enlarged. I recommend showing all spectra only in the binding energy range till 1100 eV and rescale them. All spectral features should be identified directly in Figure 1.
9. It would be very useful to collect the relative concentration of all chemical elements registered in the survey X-ray photoelectron spectra in the tables.
10. The XPS results are not clearly presented. Manuscript should be restructured. Additional information should be provided. Authors should provide C1s photoelectron spectra of all samples with deconvolution to confirm the presence of bonging between carbon and iodine atoms.
11. It is well-known that sp² component of the X-ray photoelectron spectra has an asymmetric shape from the side of higher binding energies, which is described by the Doniach-Sunjic function. Authors should implement this component with asymmetry in their deconvolution procedure. I recommend referring to publications [Journal of Environmental Chemical Engineering, 2022, 10(3), 107873], and references there.
12. Authors should estimate the probing depth of their X-ray photoelectron spectra. I recommend referring to the publication [Applied Physics A, 2009, 94, 445-448], where Authors showed example such estimations for carbon atoms.
13. The statement “The main objective of this work, iodine fixation under mild conditions is confirmed by XPS and LEIS.“ is not supported by the presented results. Additional information should be provided. Please, see comments above.
14. Statement about “Data availability” is missed.
15. Statement about “Conflict of interest” is missed.
16. All references should be verified. For example, titles of publications are missing for references [6], and [15].
17. Terminology should be corrected, e.g.

Page 4: Should be “Figure 1. Survey X-ray photoelectron spectra of HSAG-Iodinated samples...” instead of “Figure 1. XPS general survey of HSAG-Iodinated samples...”

1. Typos, errors should be corrected, e.g.

Page 4: Should be “I 3d_5/2” instead of “I3d5/2”

Page 6: Should be “50 m²/g” instead of “50 m2/g”

Comments for author File: Comments.pdf

Author Response

We are pleased to submit the revised version of the manuscript “Study of the iodine fixation over high surface area graphite (HSAG-100) under mild conditions” to be reconsidered for its publication in Reactions.

We are grateful for the thoughtful and constructive comments. We have substantially revised the manuscript to improve clarity, organization, and technical completeness. The suggested changes have significantly improved the manuscript.

 

1. The English should be improved to more clearly express the research. In some sentences, some words are missing, so it’s not possible to understand the meaning of the sentences. Generally accepted scientific terminology should be corrected.

 Response: We have carefully revised the entire manuscript for grammar, clarity, and scientific terminology. Several sentences with missing words or unclear phrasing have been corrected. To ensure consistency, we used internationally accepted terminology for carbon materials and surface analysis throughout.

 

2. The manuscript is poorly formatted. The figures are hard to read. Most of the references are not up to date.

Response: The formatting has been improved following the journal guidelines. Figures have been redrawn with higher resolution, larger font sizes, and rescaled axes. Most references have been updated, and several recent works (2022–2025) have been added to strengthen the scientific background.

 

3. Abstract is not meaningful and should be re-written.

Response: The abstract has been completely rewritten to provide a concise and meaningful summary of objectives, methodology, and findings.

 

4. The introduction doesn’t provide sufficient background and doesn’t include all relevant references. Therefore, it should be extended. Some important up-to-date investigations in this field are missing and should be added, e.g. about bromine doped graphene [Nanomaterials, 2022, 12(1), 45], and references there.

Response: The Introduction has been expanded to provide a more comprehensive background. We have incorporated the suggested references on bromine-doped graphene (Nanomaterials, 2022, 12(1), 45), as well as additional recent studies (2022–2025).

 

5. As Authors mentioned on page 2: “Carbon nanotubes (CNTs) [1], carbon nanofibers (CNFs) [2], graphite[3], and graphene-like[4] structures attract intense research interest…“ Some novel carbon nanomaterials are missing and should be added, e.g. carbyne [Polymer Degradation and Stability, 2022, 203, 110054], graphynes [Belenkov et al. chapter “Graphynes: Advanced carbon materials with layered structure” in book “Handbook on the Graphene”, M. Zhang (Ed.) Wiley-Scrivener, 2019 (DOI: 10.1002/9781119468455.ch42)], and references there.

 Response: As suggested, we have extended the introductory paragraph to include carbyne and graphynes, citing Polymer Degradation and Stability, 2022, 203, 110054 and the Wiley-Scrivener handbook chapter (2019).

 

6. More details to the section “2. Experimental methods” should be added, including information about X-ray photoelectron spectra collecting. The energy resolution and pass energy values during X-ray photoelectron spectra acquisition should be written. The procedures for X-ray photoelectron spectra calibration should be well-described. The procedure for compensation of material charging should be described. The procedure for spectra deconvolution should be well described.

Response: Section 2.3 Characterization methods now includes:

1. XPS acquisition parameters (pass energy = 20 eV for high-resolution scans, 100 eV for surveys).
2. Energy resolution (~0.85 eV).
3. Calibration procedure (C 1s = 284.6 eV).
4. Charge compensation method (flood gun, low-energy electrons).
5. Spectral deconvolution details (Shirley background, Gaussian–Lorentzian line shapes, asymmetry function for sp²).

 

7. Some words are missing in sentences: “In HSAG sample pristine only C and =(2.5at.%) is de-tected. HSAG treated samples registered iodine, larger in those prepared in decane with (IKFeD) and without iron (IKD) (~0.6 - 0.7 at%) than in those prepared in water with (IKFeW) and without iron (IKW) (~0.05 - 0.1%at).“ (page 3). It should be corrected.

Response: The sentence has been corrected to read:
“In pristine HSAG only C and O (~2.5 at.%) are detected. In iodinated HSAG samples, iodine is registered in higher amounts for those prepared in decane with (IKFeD) and without Fe (IKD) (~0.6–0.7 at.%) compared with those prepared in water with (IKFeW) and without Fe (IKW) (~0.05–0.1 at.%).”

 

8. Figure 1 is not meaningful. It should be edited and enlarged. I recommend showing all spectra only in the binding energy range till 1100 eV and rescale them. All spectral features should be identified directly in Figure 1.

Response: Figure 1 has been edited and enlarged, now limited to 0–1100 eV binding energy. All spectral features are labeled (C 1s, O 1s, I 3d, K 2p, Fe 2p).

 

9. It would be very useful to collect the relative concentration of all chemical elements registered in the survey X-ray photoelectron spectra in the tables.

Response: A new Table 1 compiles the relative atomic concentrations (at.%) of all detected elements from XPS survey spectra.

 

10. The XPS results are not clearly presented. Manuscript should be restructured. Additional information should be provided. Authors should provide C1s photoelectron spectra of all samples with deconvolution to confirm the presence of bonging between carbon and iodine atoms.

Response: We have included C 1s spectra for all samples, with deconvolution confirming the presence of C–I bonds (binding at 286.4–286.6 eV). The XPS section has been restructured for clarity.

 

11. It is well-known that sp2 component of the X-ray photoelectron spectra has an asymmetric shape from the side of higher binding energies, which is described by the Doniach-Sunjic function. Authors should implement this component with asymmetry in their deconvolution procedure. I recommend referring to publications [Journal of Environmental Chemical Engineering, 2022, 10(3), 107873], and references there.

Response: We thank the reviewer for raising this important point. The line shape of the C 1s sp² component in graphitic carbons has been debated in the literature. High-resolution studies on graphite(0001) surfaces (Phys. Rev. B 2007, 76, 153408) demonstrated that the C 1s spectrum consists of a single, highly symmetric peak with only a very small asymmetry (α ≈ 0.05). In more disordered or functionalized carbons, however, the asymmetric Doniach–Šunjić (DS) line shape has been used to better describe the sp² contribution, as recently reported for heteroatom-functionalized nanofibers (J. Environ. Chem. Eng. 2022, 10, 107873).

In the revised manuscript, we therefore adopted a cautious approach: the sp² component was fitted consistent with the presence of extended graphitic domains in the parent HSAG material, while the C–O, C–I and C–K components were modeled with symmetric Gaussian–Lorentzian shapes, reflecting their localized bonding. This treatment ensures both physical consistency and comparability with previous studies of graphite and heteroatom-functionalized carbons.

 

12. Authors should estimate the probing depth of their X-ray photoelectron spectra. I recommend referring to the publication [Applied Physics A, 2009, 94, 445-448], where Authors showed example such estimations for carbon atoms.

Response: We thank the reviewer for this observation. The recommended reference (Appl. Phys. A, 2009, 94, 445–448) indeed reports depth-dependent information for fluorinated CNTs using complementary synchrotron techniques (NEXAFS, XPS, SXE). As clarified in that work, the probing depth in XPS is not derived from EXAFS-type analysis, but rather estimated from the inelastic mean free path (IMFP, λ) of photoelectrons, which depends on their kinetic energy. For our XPS measurements, the kinetic energy of C 1s and I 3d photoelectrons corresponds to λ ≈ 1.5–2.5 nm, yielding an effective probing depth of ~3λ, i.e., ~5–7 nm. We have now included this estimation and cited Chen, Surf. Sci. Rep., 1997, 30, 1, as a general reference for IMFP-based depth approximations

 

13. The statement “The main objective of this work, iodine fixation under mild conditions is confirmed by XPS and LEIS.“ is not supported by the presented results. Additional information should be provided. Please, see comments above.

Response: We have strengthened the discussion with additional XPS (C 1s, I 3d), LEIS results, and TGA/TPD analysis, which collectively confirm iodine fixation under mild conditions. The revised Discussion section now integrates these datasets step by step to support the conclusions.

 

14. Statement about “Data availability” is missed.

Response: We have added at the end of the manuscript, in compliance with journal requirements.

 

15. Statement about “Conflict of interest” is missed.

Response: We have added at the end of the manuscript, in compliance with journal requirements.

 

16. All references should be verified. For example, titles of publications are missing for references [6], and [15].

Response: All references have been checked and corrected. Missing titles (e.g., refs [6], [15]) have been added.

 

17. Terminology should be corrected, e.g. Page 4: Should be “Figure 1. Survey X-ray photoelectron spectra of HSAG-Iodinated samples...” instead of “Figure 1. XPS general survey of HSAG-Iodinated samples...”

Response: The figure caption now reads “Figure 1. Survey XPS spectra of pristine and iodinated HSAG samples. Core-level signals are assigned (C 1s, O 1s, I 3d, Fe 2p).” as suggested.

 

18. Typos, errors should be corrected, e.g. Page 4: Should be “I 3d5/2” instead of “I3d5/2”  Page 6: Should be “50 m2/g” instead of “50 m2/g”

Response: All typos have been corrected, including “I 3d5/2” notation and proper formatting of surface area units (m² g⁻¹).

 

 

We sincerely thank the reviewer for the detailed and constructive feedback. These comments have been extremely valuable in improving the clarity, rigor, and impact of the manuscript. We believe the revised version addresses all points raised.

Round 2

Reviewer 1 Report

The authors responded adequately to the comments and suggestions, therefore I give a positive opinion.

The authors responded adequately to the comments and suggestions, therefore I give a positive opinion.

Author Response

We sincerely thank the reviewer for the positive evaluation of our revised manuscript and for acknowledging our efforts to address the comments and suggestions. We are pleased that the revisions meet the expectations and we appreciate the constructive feedback that helped us improve the quality and clarity of the work.

Reviewer 2 Report

Reviewer report on manuscript carbon-3786688-v2

1. Maroto-Valiente et al. “Study of the iodine fixation over high surface area graphite (HSAG-100) under mild conditions”

 

In the present study, the incorporation of iodine into the structure of high surface area graphite (HSAG) under mild conditions and with green solvents was studied. The efficiency in iodine fixation has been verified by XPS, LEIS, TGA, TPD, BET and XRD.

 

The manuscript can be accepted after minor revision.

Overall, Authors fulfilled almost all comments, however, some minor corrections should be done.

Questions/comments:

1. Reference [4] should be corrected, namely:

“[4] M. Brzhezinskaya, V.E. Zhivulin. Controlled modification of polyvinylidene fluoride as a way for carbyne synthesis. Polymer Degradation and Stability, 2022, 203, 110054, doi: https://doi.org/10.1016/j.polymdegradstab.2022.110054.

Reviewer report on manuscript carbon-3786688-v2

1. Maroto-Valiente et al. “Study of the iodine fixation over high surface area graphite (HSAG-100) under mild conditions”

 

In the present study, the incorporation of iodine into the structure of high surface area graphite (HSAG) under mild conditions and with green solvents was studied. The efficiency in iodine fixation has been verified by XPS, LEIS, TGA, TPD, BET and XRD.

 

The manuscript can be accepted after minor revision.

Overall, Authors fulfilled almost all comments, however, some minor corrections should be done.

Questions/comments:

1. Reference [4] should be corrected, namely:

“[4] M. Brzhezinskaya, V.E. Zhivulin. Controlled modification of polyvinylidene fluoride as a way for carbyne synthesis. Polymer Degradation and Stability, 2022, 203, 110054, doi: https://doi.org/10.1016/j.polymdegradstab.2022.110054.

Author Response

We thank the reviewer for the positive assessment of our revised manuscript and for recommending it for acceptance after minor revision. We appreciate the careful reading and constructive comments.

Concerning the specific point raised:

We have carefully revised and corrected the reference as suggested by the reviewer. It now appears in the manuscript as: “[4] M. Brzhezinskaya, V. E. Zhivulin. Controlled modification of polyvinylidene fluoride as a way for carbyne synthesis. Polymer Degradation and Stability, 2022, 203, 110054.”

We are grateful for this remark, which improves the accuracy and consistency of the reference list.

Round 3

Reviewer 2 Report

Manuscript can be accepted in the revised form.

Manuscript can be accepted in the revised form.