Advanced Catalysts for the Water Gas Shift Reaction
Round 1
Reviewer 1 Report
The study on advanced catalyst for the water gas shift reaction is interesting. However, there are a few areas required further improvement before publication. 1. Please provide more specific examples on "a great deal of research is being done on the development catalysts". What kind of research has been conducted. How is the current limitation? Any bottleneck? Why makes this study different from the past literature? The current literature is insufficient and hence the research gap is weak. 2. Why the three types of catalyst (Ni, Cu, Co) are selected in the study? What are the other types and what make these three types stand out and to be selected in the study? Please provide more explanations. 3. Please state the original purchase location for the catalysts, as well as their physical and chemical characteristics. 4. The beginning of Section 4 is repetitive and should not be included under Results and Discussion 5. Please provide error bar for all figures under results and discussion, if there is any repetition of each measurement. 6. Fig 9: Why there is a drop when the reactor temp exceed 450 deg C. Please explain and support with solid justifications. 7 There is no summary or analysis for direct comparison between the selected three catalysts. The current manuscript consists of many individual figures for each catalysts. It is suggested to have a section to summarize the differences and compare the results of each catalyst. 8. The conclusion is lengthy. Please shorten it. 9. Please provide more up-to-date references. Most of the references are 1990s and seemed the research is not up-to-date. The authors still need to spend effort to improve the literature review.
Author Response
Response to Reviewer 1 Comments
Point 1: Please provide more specific examples on "a great deal of research is being done on the development catalysts". What kind of research has been conducted. How is the current limitation? Any bottleneck? Why makes this study different from the past literature? The current literature is insufficient and hence the research gap is weak.
Response 1: The text has been added to the Introduction chapter
Point 2: Why the three types of catalyst (Ni, Cu, Co) are selected in the study? What are the other types and what make these three types stand out and to be selected in the study? Please provide more explanations. 3. Please state the original purchase location for the catalysts, as well as their physical and chemical characteristics.
Response 2: These three catalysts were selected for experimental testing because Ni based catalyst is from the group of low temperature catalysts, while Cu and Co based catalysts are representatives of high temperature catalysts. Most industrial WGS reactors use a combination of high temperature and low temperature types of catalysts. This ensures that a high degree of conversion of reactants to the desired products is achieved with acceptable catalyst reactor sizes. At high reaction temperatures, a high degree of conversion cannot be achieved for thermodynamic reasons, because with increasing temperature, the equilibrium shifts in favour of the reactants.
The text has been added to the Introduction chapter.
Point 3: Please state the original purchase location for the catalysts, as well as their physical and chemical characteristics.
Response 3: The catalysts were purchased from BASF (Germany).
The information has been added to the text.
Point 4: The beginning of Section 4 is repetitive and should not be included under Results and Discussion
Response 4: The text in Chapter 4 has been modified.
Point 5: Please provide error bar for all figures under results and discussion, if there is any repetition of each measurement.
Response 5: When testing catalysts, their catalytic activity decreases slowly. For this reason, the accuracy of the obtained measurement results has not been evaluated and therefore the error bar is not shown in the figures characterizing the measurement results.
Point 6: Fig 9: Why there is a drop when the reactor temp exceed 450 deg C. Please explain and support with solid justifications.
Response 6: At catalyst bed temperatures above 450 °C, the conversion of CO to CO2 decreases, because the thermodynamic equilibrium of a given reaction is already significantly shifted in favor of the reactants at this temperature.
The text has been added to Figure 9
Point 7: There is no summary or analysis for direct comparison between the selected three catalysts. The current manuscript consists of many individual figures for each catalysts. It is suggested to have a section to summarize the differences and compare the results of each catalyst.
Response 7: A comparison of the tested catalysts was added to the Results and Discussion chapter.
Point 8: The conclusion is lengthy. Please shorten it.
Response 8: The conclusion was shortened.
Point 9: Please provide more up-to-date references. Most of the references are 1990s and seemed the research is not up-to-date. The authors still need to spend effort to improve the literature review.
Response 9: Additional references have been added.
Reviewer 2 Report
The author raises the very good perspective paper on “Advanced Catalysts for the Water Gas Shift Reaction” This work is very interesting, and it is also clearly presented. This paper is suitable to be considered for publication after the several following issues are addressed. I recommend the minor revision of this work. 1. Please further revise the abstract part. It is more important to give the most information of this work there. 2. Transition metal nitrides and oxides are also a kind of effective catalysts that have been widely applicated for catalysis in energy and the environment. Please update some very important/landmark references in the introduction part. The intrinsic chemical/physical properties of metal elements lead to catalytic applications. Thus, it is suggested to be added to the introduction part. Journal of Cleaner Production, 2021, 318, 128544. Sustainable Materials and Technologies, 2019, 17, e00108. EcoMat, 2020, 3, e12044. 3. The English writing of this manuscript should be intensively improved, the help from senior researcher/scientist is recommended to further improve it. There are still some minor mistakes in the manuscript. 4. Perovskite oxides are also widely investigated for high-temperature reactions, please cite the below refs. Moreover, it is also suggested to add one paragraph to discuss the applications of metal catalysts for high-temperature applications. Matter, 2021. 4 (5), 1720-1734. Science of The Total Environment, 2022, 806, 151213. Separation and Purification Technology, 2021, 261, 118295. Journal of Alloys and Compounds, 2016, 654, 280-289. 5. Take care that "spaces are required between characters". 6. There are so many figures. It is strongly suggested merging several figures into one “big figure - including a, b, c, d”. 7. It is suggested to add the XRD of the catalysts.
Author Response
Response to Reviewer 2 Comments
Point 1: Please further revise the abstract part. It is more important to give the most information of this work there
Response 1: We consider the text of the abstract of the article to be sufficiently concise. The authors of the article do not consider it reasonable to further increase it with more detailed information.
Point 2: Transition metal nitrides and oxides are also a kind of effective catalysts that have been widely applicated for catalysis in energy and the environment. Please update some very important/landmark references in the introduction part. The intrinsic chemical/physical properties of metal elements lead to catalytic applications. Thus, it is suggested to be added to the introduction part. Journal of Cleaner Production, 2021, 318, 128544. Sustainable Materials and Technologies, 2019, 17, e00108. EcoMat, 2020, 3, e12044.
Response 2: References have been added.
Point 3: The English writing of this manuscript should be intensively improved, the help from senior researcher/scientist is recommended to further improve it. There are still some minor mistakes in the manuscript.
Response 3:The typos have been corrected in the text.
Point 4: Perovskite oxides are also widely investigated for high-temperature reactions, please cite the below refs. Moreover, it is also suggested to add one paragraph to discuss the applications of metal catalysts for high-temperature applications. Matter, 2021. 4 (5), 1720-1734. Science of The Total Environment, 2022, 806, 151213. Separation and Purification Technology, 2021, 261, 118295. Journal of Alloys and Compounds, 2016, 654, 280-289
Response 4: Due to the large scope of the article, we do not consider it reasonable to supplement it with additional information. The text of the article refers to other publications by the authors of the article (No. 13), where this issue is discussed in detail.
Point 5: Take care that "spaces are required between characters"
Response 5: The text has been corrected.
Point 6: There are so many figures. It is strongly suggested merging several figures into one “big figure - including a, b, c, d”.
Response 6: The individual figures contain quite a lot of information that could be useful to the readers of the article. Combining the figures together would reduce their clarity, so the authors of the article do not find it beneficial.
Point 7: It is suggested to add the XRD of the catalysts
Response 7: The results of XRD analyzes of all three tested catalysts were added to the article.
Round 2
Reviewer 1 Report
The comments are responded accordingly.
