K-Modified Co–Mn–Al Mixed Oxide—Effect of Calcination Temperature on N₂O Conversion in the Presence of H₂O and NO_x

Round 1

Reviewer 1 Report

It is believed that the author has tried to derive interesting experimental results. However, serious flaws are found in the manuscript, and detail explanations are needed.

1. The author explained the role of Co and K in the manuscript, but did not mention the role of Mn at all. A detailed description of the role of Mn and the purpose of its addition is needed.
2. The author describes the correlation between K and NO adsorption in line 238. Then, it should be shown that the change of the amount of NO adsorption depending on the calcination temperature.
3. The author mentioned the importance of the Basic site in the manuscript. If you look closely at the explanation shown in the figure, it is only relevant when there is NO in the feed gas, and if there is no NO in the feed gas, the basic site seems to have no significant correlation with the catalytic reaction. The meaning of the basic site in the condition of NO in the reaction gas should be explained in detail.
4. In line 214, it is expressed as “For evaluation of structure-activity relationship…..” The result shown in the XRD result is not a change in structure, but a change in crystallinity. Therefore, structure-activity is considered as an incorrect expression.
5. In the caption of Figure 6, it is expressed as a, b, and c, but in the figure it is indicated as 1, 2, and 3.
6. It should be written as 3.1 in line 245.
7. In CO₂-TPD analysis conditions, the ramping rate is indicated as 20^oC/min. This is an unusual analysis condition, and the ramping rate should be lowered and re-tested.

Author Response

Dear Reviewer,

Thank you for valuable comments. Revised manuscript was modified according to your recommendation. Our reply was submitted as separate file.

Kind regards

Lucie Obalová

 

Author Response File: Author Response.pdf

Reviewer 2 Report

This interesting paper is devoted to the study of the efficiency of a 2wt.%K/Co-Mn-Al mixed oxide for N2O decomposition. Particularly it is focused on the influence of the calcination temperature in the 500-700 ºC range.

To make a more complete contribution, the following points need to be addressed.

The relationship between the redox properties of the samples, as determined by H2-TPR, and the N2O conversion is not examined. In this sense, the influence of the surface Co3+/Co2+ and Mn4+/Mn3+Mn2+ molar ratios is not analysed. Activity was normalised by surface area unit but the redox properties at the surface level may also play a relevant role. Please comment on these points.

The determination of the apparent activation energy could be useful for helping to explain the catalytic results.

The linearised plots predicted by equation 2 should be included. On the basis of Figure 6, the goodness of the linearity of the kinetic results is questionable.

Author Response

Dear Reviewer,

Thank you for valuable comments. Revised manuscript was modified according to your recommendation. Our reply was submitted as separate file.

Kind regards

Lucie Obalová

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

In this revised version of the paper, the authors have addressed most of the comments I have pointed out in my previous reports. As a consequence, I have nothing against publication.