Thermal and Plasma-Assisted CO₂ Methanation over Ru/Zeolite: A Mechanistic Study Using In-Situ Operando FTIR

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

In this work, Ru was impregnated in CsUSY(38) zeolite to prepare 3Ru/CsUSY(38) catalyst, and then to study the performance and mechanism of CO2 methanation. It is interesting that the performance was studied in plasma-catalytic conditions; however, I still have some concerns. The main one is that it lacks the comparison of catalytic performance without plasma conditions. I recommend a major revision before acceptance.

(1).    Generally, the CO2 methanation reaction exhibits a high methane selectivity, while in this study, the methane was relatively low when the temperature was lower than 425oC, more explanation should be given.

(2).    What does the role of Cs in CsUSY(38) zeolite? How about the catalyst without Cs?

(3).    The conclusions are too long, it should be concise and refined, moreover, the inference should be not appeared in the conclusions.

(4).    The CsUSY(38) can be shorted as CsUSY.

(5).    The writing can be further improved. The format of the references should be uniformed, such as the Journal abbreviation.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

 

The aim is to do the present study utilizing a dielectric barrier discharge plasma to activate the CO2 methanation, synergetic effects stemming from the combination of plasma and catalyst could produce beneficial effects on the catalytic performance. Comparing the thermal and plasma-assisted CO2 methanation is useful and the manuscript is suitable for publication after certain consideration.

1. The zeolite support was used earlier in CO2 hydrogenation. This former study should be mentioned in the present manuscript: „Synergetic of Pt nanoparticles and H-ZSM-5 zeolites for efficient CO2 activation: Role of interfacial sites in high activity”, Frontiers in Materials, 127 (2019) 6p.

2. A band for monodentate formate at 1403 cm^-1 seems to be a little bit high. I prefer to use 1379 and 1580 cm^-1 for formate identification.

3. Could the effect of acidity of support on plasma assisted process?

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

This work deals with the comparison of thermal and plasma CO2 conversion to CH4. The topic (plasma) that has 10+ years of research, while thermal process is very old. The goal of this work was to compare the perspectives, efficiency and challenges for these two methods. However, I cannot see any reasonable comparison between this two and now significant results on plasma catalysis (the most important). To my opinion, the authors should present a curve similar to Figure 5, but for the plasma process. Varying e.g. plsama power. Then they should estimate the energies involved in thermal and plasma processes and then discuss it. So far this manuscript does not bearing these results.

Also, the authors should check plagiarism. (report is attached).

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors have replied the comments, and the language has been improved, I believe it can be accepted now.

Author Response

thanks for your positive commenmts

Reviewer 3 Report

Comments and Suggestions for Authors

The authors have answered to my questions and justified the novelty of this work.

The paper can be now accepted