Al2O3 Nanorod with Rich Pentacoordinate Al3+ Sites Stabilizing Co2+ for Propane Dehydrogenation
Round 1
Reviewer 1 Report
The manuscript written by Zhiping Zhao et al. presents interesting study on the effect of pentacoordinate Al3+ sites on the structural properties of Co/Al2O3 and its catalytic performance in propane dehydrogenation reaction. The provided information is logically presented and comprehensive, however some corrections are desirable according to comments.
General comments:
1. The catalysts after regeneration should be tested as well to show the stability of the catalyst.
2. Line 205. Please provide some references of such effect for similar samples containing cobalt.
Less significant:
· Line 90. Catalyst characterization instead of catalyst preparation.
· Line 109. Sample temperature is lowered instead of sample is lowered.
· Line 121. It should be “catalyst surface” at the end of the sentence, since the XPS technique provides the information from the outer surface of the sample. There is no information about the calibration method and technical data about the spectrometer and measurement conditions. The software used for deconvolution is usually provided as well.
· Line 150. Mcat should be in lower case, the same as presented in the formula.
· Line 220. Co3O4 instead of CO3O4.
· Figure 4. Intensity instead of intebsity on the Y axis.
· Line 293. Oxidation state zero should be properly indexed (superscript).
Author Response
Thank you for your suggestion. We have made extensive modifications to our manuscript to make our results convincing. Thank you again for your positive comments and valuable suggestions to improve the quality of our manuscript.
Point 1: The catalysts after regeneration should be tested as well to show the stability of the catalyst.
Response 1: We think this is an excellent suggestion. Following your recommendation, we have performed catalyst reaction regeneration and incorporated the relevant findings into the revised manuscript.
Point 2: Line 205. Please provide some references of such effect for similar samples containing cobalt.
Response 2: We have added corresponding references in this section to support our ideas [reference 29].
Less significant:
- Line 90. Catalyst characterization instead of catalyst preparation.
- Line 109. Sample temperature is lowered instead of sample is lowered.
- Line 121. It should be “catalyst surface” at the end of the sentence, since the XPS technique provides the information from the outer surface of the sample. There is no information about the calibration method and technical data about the spectrometer and measurement conditions. The software used for deconvolution is usually provided as well.
- Line 150. Mcat should be in lower case, the same as presented in the formula.
- Line 220. Co3O4 instead of CO3O4.
- Figure 4. Intensity instead of intebsity on the Y axis.
- Line 293. Oxidation state zero should be properly indexed (superscript).
Response 3: We were really sorry for our careless mistakes. Expressing gratitude for your correction. The mistake in the resubmitted manuscript has been rectified.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
- Please suggest why Co/Al2O3-NR has longer induction period than Co/Al2O3-NS during the first hour of reaction?
- Please indicate the species for binding energies shown in Table 2
- Any differences for the type of coke formed on the two catalysts?
Author Response
We sincerely aappreciate the valuable comments. As you are concerned ,there are several problems that need to be addressed. According to your nice suggestions, we have made extensive corrections to our previous manuscript,the detailed corrections are listed below.
Point 1: Please suggest why Co/Al2O3-NR has longer induction period than Co/Al2O3-NS during the first hour of reaction?
Response 1: From the SEM images, it can be observed that Co species on the Al2O3-NS support do not exhibit aggregation, indicating a high dispersion which makes its surface Co species easily reducible to Co0 and reduces the induction period of the reaction. On the other hand, Co species at both ends of Al2O3-NR show aggregation, making them less reducible and resulting in a longer induction period compared to layered catalysts [reference 9]. We added a section to explain SEM in the revised manuscript.
Point 2: Please indicate the species for binding energies shown in Table 2
Response 2: We feel sorry for our carelessness. The binding energy section of Table 2 has been improved in the revised manuscript that we have submitted. Table 2 shows that the binding energies for Co2+ and Co3+ on the Al2O3-NS are 778.1, while on the Al2O3-NR they are 778.2.
Point 3: Any differences for the type of coke formed on the two catalysts?
Response 3: The same type of coke species is present on both catalysts, and according to the weight loss curve, the temperature range for coke deposition is between 350℃-450℃. This is caused by the combustion of coke deposited on the surface of active metals and supports, which is known as hard coke and typically consists of polynuclear aromatic compounds. We added a section to explain TGA in the revised manuscript.
Author Response File: Author Response.pdf
Reviewer 3 Report
The production of Al2O3 nanorods and nanosheets and how they interact with Co(II) to yield several states of Co (CoAl2O4 and Co3O4) with varied catalytic activity and stability are covered in this article. According to the study, Co(II) can more readily bond to the five-coordinated Al3+ on nanorod Al2O3, resulting in the spinel phase of CoAl2O4 with a greater connection between the carrier and Co. The selectivity and stability of the catalyst are improved because this active phase is more stable than Co3O4 and less vulnerable to H2 reduction. The study reveals potential uses for employing Co as a propane dehydrogenation catalyst and sheds light on how the interaction force between Co and Al2O3 carriers influences dehydrogenation activity. Overall, this discovery has important ramifications for comprehending metal-oxide interaction-based catalytic processes. In terms of structure, the paper is well-written. I recommend it for acceptance pending any necessary revisions or comments from reviewers.
1. The article's main material is summarized in the abstract. When writing an abstract, it's crucial to give a quick summary of the research area before focusing on the particular subject of the paper. This will aid readers in developing a basic knowledge of the piece and assist them appreciate its significance and important ideas.
2. Table 1's title and content are not comparable. This difference may cause readers who are attempting to absorb the information to get puzzled and may even result in misunderstandings. Table 1 needs to be updated so that the title and content appropriately reflect each other.
3. The correlation between the data and the analysis's findings can be improved by rearranging the TGA data sequence and presenting it after assessing propane dehydrogenation activity. This strategy makes it easier for readers to understand the article's key point.
4. This article examines two catalysts, but their H2-TPR data showed significant differences. To eliminate the carrier's influence on the results, additional analysis and comparison are required by supplementing the data from both carriers.
Minor editing of English language required
Author Response
Response to Reviewer 3 Comments
We feel great thanks for your professional review work on our manuscript. Based on your comments, we have made corresponding modifications to the content to make the results more convincing.
Point 1: The article's main material is summarized in the abstract. When writing an abstract, it's crucial to give a quick summary of the research area before focusing on the particular subject of the paper. This will aid readers in developing a basic knowledge of the piece and assist them appreciate its significance and important ideas.
Response 1: We think this is an excellent suggestion. We have improved the abstract according to the reviewer’s suggestion.
Point 2: Table 1's title and content are not comparable. This difference may cause readers who are attempting to absorb the information to get puzzled and may even result in misunderstandings. Table 1 needs to be updated so that the title and content appropriately reflect each other.
Response 2: We sincerely thank the reviewer for careful reading. As suggested by the reviewer we have corrected Table 1's title into “Catalytic properties and carbon deposition of Co/Al2O3 catalysts.”
Point 3: The correlation between the data and the analysis's findings can be improved by rearranging the TGA data sequence and presenting it after assessing propane dehydrogenation activity. This strategy makes it easier for readers to understand the article's key point.
Response 3: We have made changes to the order of this section according to the suggestion provided by the reviewer.
Point 4: This article examines two catalysts, but their H2-TPR data showed significant differences. To eliminate the carrier's influence on the results, additional analysis and comparison are required by supplementing the data from both carriers.
Response 4: The H2-TPR results for the two types of Al2O3 did not reveal any H2 reduction peaks.
Author Response File: Author Response.pdf
