Co3O4 Catalysts for Complete Toluene Oxidation: Review including Meta-Analysis of Catalyst Activity Data
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsSome figures are not clear and needed to revise before accepted for publication in Catalysts.
Comments on the Quality of English LanguageNo
Author Response
Some figures are not clear and needed to revise before accepted for publication in Catalysts.
Our reply: We appreciate the reviewer's comment. We have updated Figures 12, 13, and 14. However, due to the poor resolution quality of the initial figures, Figures 13C and 14B cannot be further improved.
Reviewer 2 Report
Comments and Suggestions for AuthorsIn this paper, Ioannides et al. conducted a review of Co3O4 catalysts for the complete oxidation of toluene, offering insights into the synthesis and physicochemical characterization of these catalysts. Their conclusions suggest that the specific surface area does not exert a significant influence on the specific activity of Co3O4 catalysts for the complete oxidation of toluene. The specific reaction rates differ due to factors such as morphology, different exposed crystallographic planes, surface concentration, and oxidation state of cobalt cations. This review paper is suitable for publication with some minor revisions.
1. The authors have concluded the comprehensive characterization and design of Co3O4 catalysts for toluene oxidation, and it is recommended to include the reaction mechanism.
2. In the characterization of toluene oxidation-based catalysts, it is advisable to include the introduction of characterization related to gas-solid or liquid-solid interfaces in Section 3.
3. The author should consider citing pertinent studies that explore the application of metal nanoparticles. For example, they could consider referencing the following sources: Small 2022, 18 (16), 2106893.; J. Catal. 2021, 396, 342.
4. It is recommended to include a section on "Challenges and Perspectives" in Section 5 to provide readers with insights into the forefront of this research area.
Comments for author File: 
Comments.pdf
The quality of English is good enough.
Author Response
In this paper, Ioannides et al. conducted a review of Co3O4 catalysts for the complete oxidation of toluene, offering insights into the synthesis and physicochemical characterization of these catalysts. Their conclusions suggest that the specific surface area does not exert a significant influence on the specific activity of Co3O4 catalysts for the complete oxidation of toluene. The specific reaction rates differ due to factors such as morphology, different exposed crystallographic planes, surface concentration, and oxidation state of cobalt cations. This review paper is suitable for publication with some minor revisions.
1) The authors have concluded the comprehensive characterization and design of Co3O4 catalysts for toluene oxidation, and it is recommended to include the reaction mechanism.
Our reply: We thank the reviewer for the comment. We have described the reaction mechanism for the total oxidation of toluene, and we have added two more references for this purpose (please see lines 66-80)
2) In the characterization of toluene oxidation-based catalysts, it is advisable to include the introduction of characterization related to gas-solid or liquid-solid interfaces in Section 3.
Our reply: We appreciate the reviewer's suggestion. We have included a brief description of H2-TPR and O2-TPD principles in Sections 3.4 (please see lines 514-521) and 3.5 (please see lines 575-581), respectively.
3) The author should consider citing pertinent studies that explore the application of metal nanoparticles. For example, they could consider referencing the following sources: Small 2022, 18 (16), 2106893.; J. Catal. 2021, 396, 342.
Our reply: We thank the reviewer for the suggested references which are greatly appreciated. Nevertheless, we noticed that the materials employed refer to porous carbon-supported Pd nanoparticles for selective hydrogenation and hydrodeoxygenation (HDO) of biomass, which are not relevant to our materials (Co3O4) and the total oxidation of toluene. We believe that the addition of these references would rather disorient the reader rather than provide useful background regarding the employed catalytic materials.
4) It is recommended to include a section on "Challenges and Perspectives" in Section 5 to provide readers with insights into the forefront of this research area.
Our reply: We thank the reviewer for the comment, and we have included “Challenges and Perspectives” section along with overall conclusions.
Reviewer 3 Report
Comments and Suggestions for AuthorsThe authors briefly review the synthesis methods and physicochemical properties characterization of the Co3O4 catalysts, elucidate the structure sensitivity of toluene oxidation over these catalysts, and correlated the specific reaction rate of toluene oxidation with physicochemical properties (specific surface area, facet, and Co3+/Co2+ ratio). This work contains some useful information and could be considered for publication. However, the authors should revise their manuscript before acceptance for publication according to the following comments:
1. There is no need to use "(C7H8)" in the title.
2. What does the "meta-analysis" mean?
3. The authors should include the conclusive remarks on the influence of specific surface area, facet, and Co3+/Co2+ ratio on catalytic activity of the Co3O4 catalysts in the abstract.
4. Some tables summarizing the catalysts, preparation methods, main physicochemical properties, reaction conditions, specific reaction rates, and references should be provided.
5. The formats of the references list should be unified according to the requirements of this journal.
Comments on the Quality of English LanguageThere are some inappropriate English words or expressions in the manuscript. The authors should carefully polish the English of the whole manuscript.
Author Response
The authors briefly review the synthesis methods and physicochemical properties characterization of the Co3O4 catalysts, elucidate the structure sensitivity of toluene oxidation over these catalysts, and correlated the specific reaction rate of toluene oxidation with physicochemical properties (specific surface area, facet, and Co3+/Co2+ ratio). This work contains some useful information and could be considered for publication. However, the authors should revise their manuscript before acceptance for publication according to the following comments:
1) There is no need to use "(C7H8)" in the title.
Our reply: We agree with the reviewer, and we revised the title of the manuscript to ‘’Co3O4 catalysts for complete toluene oxidation: Review including meta-analysis of catalyst activity data’’, as suggested.
2) What does the "meta-analysis" mean?
Our reply: We thank the reviewer for the meaningful comment. The "meta-analysis" term is used to denote the secondary analysis of literature data extracted after careful consideration of the catalytic evaluation measurements aiming at elucidating the structure sensitivity of toluene oxidation over Co3O4 catalysts.
3) The authors should include the conclusive remarks on the influence of specific surface area, facet, and Co3+/Co2+ ratio on catalytic activity of the Co3O4 catalysts in the abstract.
Our reply: We thank the reviewer for the comment. We have revised accordingly the abstract.
4) Some tables summarizing the catalysts, preparation methods, main physicochemical properties, reaction conditions, specific reaction rates, and references should be provided.
Our reply: We agree with the reviewer, and we have added the summarizing Table 1.
5) The formats of the references list should be unified according to the requirements of this journal.
Our reply: We thank the reviewer for the comment, and we have adjusted the references.
