Deposition of Selective Catalytic Reduction Coating on Wire-Mesh Structure by Atmospheric Plasma Spraying
Round 1
Reviewer 1 Report
This paper is a study on the fabrication and performance evaluation of SCR catalyst using plasma spray technique. The catalyst produced plasma spray technology is very interesting in that the author applies the spray technology, the results of the study in terms of catalyst production potential confirmed by the analysis of catalysts produced via spray technology is significant. However, there is a lack of description and analysis contents of experiment contents and result analysis. Therefore, detailed explanations and analysis of the research process and results are necessary, and it is necessary to decide whether or not to issue papers through further review.
1. In the case of the existing SCR catalyst, it was supported on a monolith and commercialized, and a metal mesh was selected as a support to replace it. There is a need for specific reasons and a comparison through quantification. For example, it is preferable to compare and explain the specific values instead of merely reducing the differential pressure or improving the thermal characteristics. The author says it is excellent in the coating of metal surfaces, but it is not a general characteristic. It is necessary to specify specific conditions in special circumstances. (41-44 lines and 51 lines)
2. Lack of explanation of catalyst manufacturing process using plasma (eg, power required for plasma, coating time, etc.) (77-78 lines)
3. When coating metal mesh surfaces, is it evenly coated before and after the mesh? If so, for what reasons? Only one direction of the spray direction and the metal mesh face, why is it becoming uniform?
4. The author explains that the NOx removal performance of the metal mesh compared to the metal plate is somewhat improved, which is the reason for the increase in the area due to the structural characteristics. However, it increases only in the range of 300 to 350 Celsius degrees, and decreases in other temperature ranges. If the area is simply increased, the performance should increase at all temperature ranges. There is a lack of explanation for this.
5. It is believed that the present study suggests the possibility of preparing a catalyst by plasma spray coating and its performance evaluation. If so, it is necessary to compare the characteristics of the catalyst itself in more detail according to the difference in catalyst production method. For example, does plasma spray coating show better adhesion than conventional methods? What is the BET change on the catalyst surface? Can you control the thickness or uniformity of the catalyst depending on the coating time or the plasma power? Is there any change in coating performance due to vibration or temperature change after coating against actual application? And so on.
Author Response
Thank you very much for giving us an opportunity to revise the manuscript. We also deeply appreciate the reviewers for their positive and constructive comments.
All these comments and suggestions are valuable, which make the paper more readable and help us to develop the work further. We studied the comments carefully and revised the manuscript. We marked all the changes in red color in the manuscript. Here we submit a new version of the manuscript for your kind consideration. Attached you may also find a point-to-point response to the reviewers’ comments.
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
This manuscript reported the study of MnOx-CeO2/TiO2 catalysts prepared by atmospheric plasma spraying for selective catalytic reduction. My first suggestion before the article can be accepted is that it should be revised with an improvement of the writing. I also have other observations that could be addressed by the authors.
In the introduction part, Mn-based catalysts were reported as an excellent candidate for exhaust emission containing SO2. This is not correct. The formation of all materials (company, purity) for catalyst preparation should be added. The N2 selectivity and NH3 conversion of SCR reaction should be added and explained in the parts 3.3. and 3.4 as the NOx conversion decreased significantly above 350 °C. The SCR catalytic performance of this catalyst is not good for the application if only showing high NO conversion without the information of NO2 and N2O formation. Moreover, the maximum of NO conversion of 65 % is not high enough and just in the narrow range of temperature (300-350 °C). The stability of this catalyst and the effect of SO2 on the catalytic performance need to be investigated.
Author Response
Thank you very much for giving us an opportunity to revise the manuscript. We are deeply appreciated for your positive and constructive comments.
All these comments and suggestions are valuable, which make the paper more readable and help us to develop the work further. We studied the comments carefully and revised the manuscript. We marked all the changes in red color in the manuscript. Here we submit a new version of the manuscript for your kind consideration. Attached you may also find a point-to-point response to the comments.
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Some questions were answered. After revising, the quality of the manuscript is improved. However, NH3-SCR catalytic performance of this catalyst is not good for the application if only showing high NO conversion without the information of NO2 and N2O formation. Therefore the N2 selectivity or N2O formation needs to be added.
Author Response
Please the attachment.
Author Response File: Author Response.pdf
