Development of Catalysts for the Electrochemical CO2 Reduction Reaction
, Yuhuan Fei *, Meng Zhou * and Hongmei Luo *
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsMDPI-Inorganics
Comments on Manuscript Inorganics-3790593 - Review
Title: Development of Catalysts for Electrochemical CO2 Reduction Reaction
This review presents the CO2 reduction with different catalysts using electrocatalysis for the reduction focusing the product selectivity (formate, CO, and multicarbon products). Several catalysts were studied, and the most significant were Au, Cu and CNT, with different structures and morphologies. These catalysts were evaluated electrochemically, using as parameter the Faraday Efficiency (FE) and selectivities of important products, like ethylene, ethylene, oxygenated compounds due to the intermediate formation of formates. In fact, the CO2 reduction are currently in focus using different catalytic processes, for the formation of oxygenated compounds like DME, acetic acids and VAM, through the methane reaction sith CO2 or CO2 hydrogenation. The catalysts are the key problems, and many of them similar to these catalyst. But, in these cases the selectivity and activity are presented as molar fraction and as TOF, which are the parameters for comparing with other methods. So, for comparison it would be interesting to use similar parameters, and discuss the efficiency of the catalysts.
Indeed, this review concluded that Au, Cu and in particular CNT were comparatively the most efficient catalysts. Is this in accordance with the reported articles using catalytic systems?
The development of the Au, Cu and other catalyst are presented in figures 1,3 and 4, but no surface properties were included. As seen, there are different particle forms, and size distribution, but no structural properties, which are essential to understand the adsorption and surface reactions. In fact, as mentioned there are “intrinsic complexity of the eCO2RR, involving multiple competing pathways and intermediates”, for determining the activity and selectivity to selected products.
It is an excellent review, but explain these comments.
Author Response
We appreciate your very professional comments, the corresponding changes have been made, please see the attached file.
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Author Response.docx
Reviewer 2 Report
Comments and Suggestions for Authorscheck attached file
Comments for author File: 
Comments.pdf
Author Response
We appreciate your professional comments, the corresponding changes have been made, please see the attached file.
Author Response File: Author Response.docx
Reviewer 3 Report
Comments and Suggestions for AuthorsThe review paper titled "Development of Catalysts for Electrochemical CO2 Reduction Reaction" addresses a topic of high importance in the field of electrochemical CO2 reduction and is expected to attract significant attention and citations. However, the current manuscript still needs substantial improvement in terms of content completeness, richness, and the highlighting of seminal works. Therefore, I recommend major revision before publication. Below are my specific suggestions:
1. As a review paper, when reproducing figures from other works, the authors should obtain the source images whenever possible to ensure maximum quality and resolution in the assembled figures. It should also be noted that many journals allow only a limited number of free figures—typically around three per article. The exact permissions can be verified via https://marketplace.copyright.com/. Appropriate copyright information must be included in the figure captions for any reused figures; see Adv. Mater. 2017, 29, 1601694 for reference (citation is optional).
2. The content of the review needs further enrichment. Four highlighted studies are insufficient to fully represent the breadth of seminal work in the rapidly advancing field of electrochemical CO2 reduction. The authors should add more representative studies as highlighted examples. Additional high-quality figures should be introduced, including original schematics or summary diagrams created by the authors.
3. In situ characterization techniques—such as in situ infrared, in situ Raman, and in situ XPS—are crucial for understanding the electrochemical CO2 reduction reaction. These methods should be discussed in detail and can also serve as highlighted examples.
4. DFT calculations are another essential tool for mechanistic elucidation of the electrochemical CO2 reduction reaction. Topics such as free-energy diagrams, transition-state analyses, and electronic-structure analyses should be thoroughly expanded and discussed.
5. The section on metal-free electrocatalysts currently lacks a dedicated figure highlighting key studies, which is a notable weakness. Moreover, while carbon and nitrogen-doped carbon materials are discussed, emerging and highly studied materials such as COFs and conjugated polymers are absent. The authors should incorporate these hot topics into the review.
Author Response
We appreciate your professional comments, the corresponding changes have been made, please see the attached file.
Author Response File: Author Response.docx
Round 2
Reviewer 3 Report
Comments and Suggestions for AuthorsThe authors have carefully addressed all the requested revisions. I recommend acceptance of the manuscript in its current form.
