Advanced XPS-Based Techniques in the Characterization of Catalytic Materials: A Mini-Review
, Jinqi Wu 1, Weilin Dai 2 and Taohong Huang 1,*
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe presented Review Article devoted to the Advanced XPS-based Techniques in the Characterization of Catalytic Materials.
The authors considered the possibilities to obtain unique information about the surface using several advanced XPS-based techniques. The topic is a really important and interesting for the catalytic community. The authors consider the XPS-based analysis methods such as ion scattering spectroscopy (ISS), high energy X-ray source and argon ion sputtering, giving different depth information about the sample.
The possibility to provide the investigation of catalysts surface with a different depth is really important for the catalysis in order to make a conclusion about the active component nature. Therefore this subject area is really demand.
Another interesting type of XPS-based technique is so called «quasi in situ XPS» which is really important for the catalysts unstable for air. The introduction clearly lays out reasons for discussion of the application of such unique techniques; manuscript is well written, complying with the standards for a scientific publication. In the conclusions authors discussed the opportunities that considered advanced XPS techniques could give and prospective for the development of such techniques in order to get new information about catalysts.
Additionally I would like to mention that in review the authors discussed very recent and actual articles devoted to the subject. Overall this review is really interesting for the wide range of scientists from catalytic community.
Finally, from my opinion the manuscript can be accepted for publication in Catalysts journal after the following issues are taken into account in a revised version: (1) From my opinion the additional XPS-based technique should be added to the Paragraph 2. Conventional XPS Technology and Functional Accessories (Analysis at different depths). The additional possibility to provide the depth-profiling experiments for catalytic systems could be achieved using the Synchrotron radiation based XPS, it gives the possibility to provide the non-destructive depth profiling by variation of the excitation energy. See for example: https://doi.org/10.1039/C7FD00219J, https://doi.org/10.1016/j.apsusc.2016.01.173, https://link.springer.com/article/10.1007/s11244-015-0534-2, https://doi.org/10.1016/j.cattod.2015.05.029, etc
Author Response
Reviewer 1
Comments 1: The presented Review Article devoted to the Advanced XPS-based Techniques in the Characterization of Catalytic Materials. The authors considered the possibilities to obtain unique information about the surface using several advanced XPS-based techniques. The topic is a really important and interesting for the catalytic community. The authors consider the XPS-based analysis methods such as ion scattering spectroscopy (ISS), high energy X-ray source and argon ion sputtering, giving different depth information about the sample. The possibility to provide the investigation of catalysts surface with a different depth is really important for the catalysis in order to make a conclusion about the active component nature. Therefore this subject area is really demand.
Another interesting type of XPS-based technique is so called «quasi in situ XPS» which is really important for the catalysts unstable for air. The introduction clearly lays out reasons for discussion of the application of such unique techniques; manuscript is well written, complying with the standards for a scientific publication. In the conclusions authors discussed the opportunities that considered advanced XPS techniques could give and prospective for the development of such techniques in order to get new information about catalysts. Additionally I would like to mention that in review the authors discussed very recent and actual articles devoted to the subject. Overall this review is really interesting for the wide range of scientists from catalytic community.
Finally, from my opinion the manuscript can be accepted for publication in Catalysts journal after the following issues are taken into account in a revised version: (1) From my opinion the additional XPS-based technique should be added to the Paragraph 2. Conventional XPS Technology and Functional Accessories (Analysis at different depths). The additional possibility to provide the depth-profiling experiments for catalytic systems could be achieved using the Synchrotron radiation based XPS, it gives the possibility to provide the non-destructive depth profiling by variation of the excitation energy. See for example: https://doi.org/10.1039/C7FD00219J, https://doi.org/10.1016/j.apsusc.2016.01.173, https://link.springer.com/article/10.1007/s11244-015-0534-2, https://doi.org/10.1016/j.cattod.2015.05.029, etc
Response 1: Thanks for your suggestions, we have added the synchrotron radiation based XPS in Paragraph 2, the relevant content has been highlighted, see Page 1, line 39-43.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe author wrote a mini-review based on additional techniques to enhance our understanding of the typical XPS instrument. The manuscript is well organized and written. I suggest publishing it with minor revisions, which are listed below.
Page 1 – Line 12: The ion scattering spectroscopy (ISS) does not provide deeper information
Page 1 – Line 27: remove “limited penetration ability of X-ray”, because it is micrometer level. Maybe you can say “due to not the limited penetration ability of X-ray, but the inelastic mean free path of emitted photoelectrons from the material surface”
Page 2 – Line 49: use abbreviation “near-ambient pressure XPS (NAPXPS)”
Page 2 – Line 70-71: OER, SACs: what are they?
Page 2 – Line 86: ESA abbreviation is not necessary and term of “electrostatic” is a bit confusing. Better to use “the electron energy analyzer of XPS…”
Page 4 – Line 130: I suggest to change the phrase of “always within 10 nm” to “maximum within 10 nm for Al Kα X-ray source”
Page 4 – Line 144: The authors mention both angle-dependent XPS and ARXPS techniques, but they only (most likely) illustrate angle-dependent XPS technique in Figure 3. It would be preferable to have cartoon illustrations ready for the ARXPS method as well.
Page 5 – Line 172: I suggest to change the phrase of “to achieve higher energy resolution and deeper analysis depth” to “to achieve higher energy resolution and/or deeper analysis depth” because achieving one of them from a synchrotron source already valuable.
Page 5 – Line 173: I suggest to change the phrase of “synchrotron radiation testing resources” to “synchrotron radiation beam sources”
Page 6 – Line 224: I suggest to change the phrase of “less damage” to “less chemical damage” or “less chemical and electronic damage”
Page 11 – Line 374: The authors limit their discussion to recent and personally self-related applications of the light stimuli with XPS in the fourth section. The foundation of this technique is quite old, and it has been used for a variety of purposes, including measuring accurate band structure, determining the type of doping in a semiconductor, studying charge transfer dynamics, conducting photo-resistor/current, pump and pump-probe measurements, etc. It will be really beneficial for this review article if these applications were summarized in a few sentences at the beginning of the section.
Page 13 – Line 462: I am grateful to the authors for their insightful commentary on recent erroneous XPS data evaluation.
Author Response
Reviewer 2
The author wrote a mini-review based on additional techniques to enhance our understanding of the typical XPS instrument. The manuscript is well organized and written. I suggest publishing it with minor revisions, which are listed below.
Comments 1: Page 1 – Line 12: The ion scattering spectroscopy (ISS) does not provide deeper information
Response 1: Thanks for your suggestions, we have replaced the content with the following “This mini-review introduces and summarizes the primary applications of XPS-based analysis methods, including ion scattering spectroscopy (ISS) for analyzing surface single atomic layer, angle-resolved XPS, high energy X-ray source and argon ion sputtering, each providing different depth information about the sample.”. See Page 1, line 11-14.
Comments 2: Page 1 – Line 27: remove “limited penetration ability of X-ray”, because it is micrometer level. Maybe you can say “due to not the limited penetration ability of X-ray, but the inelastic mean free path of emitted photoelectrons from the material surface”
Response 2: Thanks for your suggestions, we have made revisions in the main text, and the relevant content has been highlighted. See Page 1, line 27-29.
Comments 3: Page 2 – Line 49: use abbreviation “near-ambient pressure XPS (NAPXPS)”
A: Thanks for your suggestions, we have made revisions in the main text, and the relevant content has been highlighted. See Page 2, line 52-53.
Comments 4: Page 2 – Line 70-71: OER, SACs: what are they?
Response 4: Thanks for your suggestions, OER means electrocatalytic oxygen evolution reaction, SACs means Pt single-atom catalysts, we have made revisions in the main text, and the relevant content has been highlighted. See Page 2, line 71-73.
Comments 5: Page 2 – Line 86: ESA abbreviation is not necessary and term of “electrostatic” is a bit confusing. Better to use “the electron energy analyzer of XPS…”
Response 5: Thanks for your suggestions, we have made revisions in the main text, and the relevant content has been highlighted. See Page 3, line 101.
Comments 6: Page 4 – Line 130: I suggest to change the phrase of “always within 10 nm” to “maximum within 10 nm for Al Kα X-ray source”
Response 6: Thanks for your suggestions, we have made revisions in the main text, and the relevant content has been highlighted. See Page 4, line 144.
Comments 7: Page 4 – Line 144: The authors mention both angle-dependent XPS and ARXPS techniques, but they only (most likely) illustrate angle-dependent XPS technique in Figure 3. It would be preferable to have cartoon illustrations ready for the ARXPS method as well.
Response 7: Thanks for your suggestions, we have added cartoon illustration for ARXPS in the main text, see figure 4, the relevant content has been highlighted. See Page 5, line 163-164.
Comments 8: Page 5 – Line 172: I suggest to change the phrase of “to achieve higher energy resolution and deeper analysis depth” to “to achieve higher energy resolution and/or deeper analysis depth” because achieving one of them from a synchrotron source already valuable.
Response 8: Thanks for your suggestions, we have made revisions in the main text, and the relevant content has been highlighted. See Page 6, line 203.
Comments 9: Page 5 – Line 173: I suggest to change the phrase of “synchrotron radiation testing resources” to “synchrotron radiation beam sources”
Response 9: Thanks for your suggestions, we have made revisions in the main text, and the relevant content has been highlighted. See Page 6, line 203.
Comments 10: Page 6 – Line 224: I suggest to change the phrase of “less damage” to “less chemical damage” or “less chemical and electronic damage”
Response 10: Thanks for your suggestions, we have made revisions in the main text, and the relevant content has been highlighted. See Page 7, line 254.
Comments 11: Page 11 – Line 374: The authors limit their discussion to recent and personally self-related applications of the light stimuli with XPS in the fourth section. The foundation of this technique is quite old, and it has been used for a variety of purposes, including measuring accurate band structure, determining the type of doping in a semiconductor, studying charge transfer dynamics, conducting photo-resistor/current, pump and pump-probe measurements, etc. It will be really beneficial for this review article if these applications were summarized in a few sentences at the beginning of the section.
Response 11: Thanks for your suggestions, we have made revisions in the main text, and the relevant content has been highlighted. See Page 12, line 410-420.
Comments 12: Page 13 – Line 462: I am grateful to the authors for their insightful commentary on recent erroneous XPS data evaluation.
Response 12: Thanks for your agreement.
Reviewer 3 Report
Comments and Suggestions for AuthorsThis review entitled “Advanced XPS-based Techniques in the Characterization of Catalytic Materials: A Mini-Review” deals on the applications of XPS-ISS, HAXPES and In situ reactor XPS in Catalysis. This minireview is very opportune and is of interest of the readers on Catalysis, however, some sections must be extended. This review merits its publication in Catalysts but major changes are necessary prior to its acceptance. Some suggestions are indicated as follows.
1.- This paragraph at the beginning of section 2 “XPS provides both qualitative and quantitative insights into the chemical composition of a material's surface to a depth of approximately 10 nm. It delivers elemental information with a detection sensitivity between 0.1-1 at.% for all elements except H and He” is a repetition a paragraph of the Introduction section. Please, remove it.
2.- This sentence “The presence of both Pt2+ and Pt4+ species in the catalyst, indicating the oxidation state of Pt atoms and the successful formation of the alloyed structure without metallic Pt particles” is wrong. Pt(II) and Pt(IV) cannot form an alloy.
3.- Please, use the same temperature unit along the text.
4.- The section dedicated to ARXPS must include examples with more different angles and discussing studies in depth
5.- The section dedicated to XPS and Photocatalysis must be extended with more examples.
Comments on the Quality of English LanguagePlease check some typos.
Author Response
Reviewer 3
Comments and Suggestions for Authors
This review entitled “Advanced XPS-based Techniques in the Characterization of Catalytic Materials: A Mini-Review” deals on the applications of XPS-ISS, HAXPES and In situ reactor XPS in Catalysis. This minireview is very opportune and is of interest of the readers on Catalysis, however, some sections must be extended. This review merits its publication in Catalysts but major changes are necessary prior to its acceptance. Some suggestions are indicated as follows.
Comments 1: This paragraph at the beginning of section 2 “XPS provides both qualitative and quantitative insights into the chemical composition of a material's surface to a depth of approximately 10 nm. It delivers elemental information with a detection sensitivity between 0.1-1 at.% for all elements except H and He” is a repetition a paragraph of the Introduction section. Please, remove it.
Response1: Thanks for your suggestions, we have made revisions in the main text, and the relevant content has been highlighted. See Page 2, line 63-64.
Comments 2: This sentence “The presence of both Pt2+ and Pt4+ species in the catalyst, indicating the oxidation state of Pt atoms and the successful formation of the alloyed structure without metallic Pt particles” is wrong. Pt(II) and Pt(IV) cannot form an alloy.
Response 2: Thanks for your suggestions, we have made revisions in the main text, and the relevant content has been highlighted. See Page 2, line 75-78.
Comments 3: Please, use the same temperature unit along the text.
Response 4: Thanks for your suggestions, we have checked the temperature units to ensure consistency. Currently, only a few of the Figure images have inconsistent temperature units.
Comments 4: The section dedicated to ARXPS must include examples with more different angles and discussing studies in depth.
Response 4: Thanks for your suggestions, we have added content in ARXPS part, the relevant content has been highlighted. See Page 5-6, line 184-195.
Comments 5: The section dedicated to XPS and Photocatalysis must be extended with more examples.
Response 5: Thanks for your suggestions, we have added content in XPS and photocatalysis part, the relevant content has been highlighted. See Page 2, line 78-90, Page 12, line 410-420, Page 13, line 466-470.
Comments 6: Comments on the Quality of English Language. Please check some typos.
Response 6: Thanks for your suggestions, we have checked again.
Round 2
Reviewer 3 Report
Comments and Suggestions for AuthorsThe revised version of this mini-review has considered all my suggestions, and now I can recommend its publication in Catalysts.
