In Situ DRIFTS Study of Single-Atom, 2D, and 3D Pt on γ-Al₂O₃ Nanoflakes and Nanowires for C₂H₄ Oxidation

Round 1

Reviewer 1 Report

The article "In Situ DRIFTS Study of Single-Atom, 2D, and 3D Pt on γ-Al₂O₃ nanoflakes and nanowires for C₂H₄ Oxidation" is devoted to the synthesis and detailed study of the Single-Atom, 2D, and 3D Pt nanoflakes and nanowires.  In the article, the influence of the particle size of platinum on the activity in the C2H4 Oxidation reaction was studied in detail, and the optimal particle size was established. The work used a complex of modern research methods, including in-situ DRIFTS. This study is of undoubted interest, the article is well written, the conclusions are not in doubt. Thus, this article can be accepted for publication.

Author Response

Dear reviewer 1:

Thank you for your decision and constructive comments on my manuscript.

Author Response File: Author Response.docx

Reviewer 2 Report

Review of the manuscript Processes 1894083 for the Authors: In the paper, the results of the influence of two different crystal faces of γ-Al2O3 structures (nanoflakes and nanowires) on the size, shape and finally on the catalytic performance of the alumina-supported Pt-catalyst (Pt/γ-Al2O3) are reliably presented. The main goal of the paper is the identification and characterization of the active sites of the Pt/γ-Al₂O₃ catalyst primarily by the in-situ DRIFTS method and accompanying XRD, TEM, XPS, HAADF-STEM methods. Also, based on the mentioned DRIFTS method, the authors proposed the steps of the surface reaction of C₂H₄ for Pt/γ-Al₂O₃ catalyst. The article is easy to read because the authors provide concise information throughout the paper, adequately referring to figures, tables and literature. Also, the attached results (figures, tables and explanations) are easy to understand.

From the originality point of view, only limited novelty is presented. All in all, with the aim of improving the quality of the paper, I must point out certain minor shortcomings:

-> For the volume of the Teflon reactor, two different units of measurement (mL and cc) were used, and the use of two different fonts for the ℃ sign was observed.

-> Minor errors were also observed, e.g. PAl-NF instead of PtAl-NF (Lines 246-247), missing γ in Pt/-Al2O3 (line 263) and several grammatical errors, e.g. line 136 "cell that had been warmed" (has)

-> In subtitle 2.5, when explaining the DRIFTS experiment, it is not explained why the samples were heated to 400 ℃. Also, most of that subtitle, more precisely from line 116 to 138, should be written more clearly.

-> In lines 58-61 crystal faces (110) and (100) appear to be interchanged with respect to Al-NF and Al-NW ordering.

-> For readers (scientists) who are new to this field, it would be good to note what the abbreviation (S) stands for in Table 2.

-> It would be good to explain in a little more detail (a sentence or two) what the Mars–van Krevelen mechanism is.

-> The only “serious” objection to the paper is the lack of XRD pattern for γ-AlOOH sample obtained before calcination at 550 ℃ in Figure 2. Given that the authors wrote: „The sample prepared in part 2.2 using Al3+/AlO2- exhibited highly distributed γ-AlOOH-based nanoflakes. After calcination at 550 ℃, γ-AlOOH transformed into γ-Al2O3 [32-34], and the TEM image of γ-Al2O3 nanoflakes (Al-NF) has been depicted in Figure 3a.“. I consider that this statement related to the phase transition from γ-AlOOH to γ-Al₂O₃ due to calcination at 550 ℃ should be proven with the change in XRD pattern in Figure 2.

-> Also, in good faith with the aim of better recognition of this work and the use of the in-situ DRIFTS method for the identification and characterization of active sites. I suggest changing the title to something catchier.

Finally, only after supplementing Figure 2 with the XRD pattern of γ-AlOOH and correcting the minor shortcomings mentioned above I can suggest accepting the paper. For now I suggest minor revision.

Author Response

Dear reviewer2 :

Thank you for your decision and constructive comments on my manuscript. We have carefully considered the suggestion of Reviewer and make some changes. We have tried our best to improve and made some changes in the manuscript.

The yellow part that has been revised according to your comments. Revision notes, point-to-point, are given.

Author Response File: Author Response.docx

Reviewer 3 Report

The submitted manuscript describes research on a material based on various platinum particles on γ-Al2O3. The study is important from a theoretical point of view, helping to understand the mechanism of the catalyst. from a practical point of view, the study of the prospect is important, since it is aimed at the development of materials for the processing of volatile organic compounds

Has the influence of the nature of the platinum precursor on the morphology and properties of the resulting material been studied? Is it possible to use the more readily available Chloroplatinic acid?

 

Calcination at 550 С Request complete removal of hydroxyl groups? Is the sufficiency of temperature measurement by thermogravimetry justified?

 

During storage of the obtained material, is moisture absorption from the air and surface hydration observed?

Figure 5 shows the IR spectra, in which the authors deposit a fragment of the band in the region of 3700 cm-1 in the complex signal of hydroxyl groups to generate the Pt-OH bond. Is there any literature data? If possible, please provide a reference. Or is the conclusion made on the basis of general theoretical ideas?

 

Has the catalytic activity of the material been studied depending on the time of its storage after preparation?

Author Response

Dear reviewer3 :

Thank you for your decision and constructive comments on my manuscript. We have carefully considered the suggestion of Reviewer and make some changes. We have tried our best to improve and made some changes in the manuscript.

The yellow part that has been revised according to your comments. Revision notes, point-to-point.

Author Response File: Author Response.docx