Optimized Ni, Co, Mn Oxides Anchored on Graphite Plates for Highly Efficient Overall Water Splitting

Round 1

Reviewer 1 Report

In this manuscript, Lin et al. studied a wide range of bimetallic Ni, Mn, Co, based oxide materials supported on graphite plate as highly efficient water electrolysis catalysts and also for half-reactions (i.e., oxygen evolution reaction (OER) and hydrogen evolution reaction (HER)). The results were well supported by combined theoretical and experimental techniques. The control samples were systematically evaluated for water electrolysis. A moderate doping amount was found to contribute to enhanced water electrolysis performance, with Co2.1Mn0.9O4 delivering optimum performance. Overall, this work has good novelty and can appeal to the readership of the Catalysts journal. I believe the work is suitable for publication. However, the current manuscript still require some revision to further improve quality and clarity. Below are some more detailed comments.

1. It might not be a good idea to include the element symbols (Ni, Co, Mn) as the keywords because they are too broad terms.

2. In Abstract, the authors mentioned “The calculation predicted that a small amount of Ni- or Co- doped MnO, Ni- or Mn- doped Co3O4 will show better catalytic activity for water splitting.” Why was “better” used here? These doped materials showed better performance compared to what?

3. To appeal to a broader readership, recent works on water electrolysis are suggested to be referenced in the Introduction (e.g., Small, 2021, 17, 2101573; Energy Technology, 2022, 10, 2200573; Small Methods, 2022, 6, 2201099).

4. Please note that for the overall water splitting, usually a two-electrode testing system was used. Therefore the data would not look like those presented in Fig. 5a and 5f. The authors are suggested to refer to related literature to make revision necessary.

5. In Fig. 5b, the Tafel slope was calculated to be 172.04 mV dec-1. Is it just the Tafel slope of the OER part? Please note that usually Tafel plots are constructed for the half-reactions like either OER or HER but seldom for overall water splitting.

6. In the manuscript, the authors are recommended to justify why graphite plate was selected/used as the substrate.

7. Minor change to the text is needed. For instance, last sentence of the Introduction, “development of bimetallic oxide catalytic”, here “catalytic” needs to be revised into “catalysts”. Also check through the manuscript to make any necessary revisions.

 

8. Typos need to be corrected. For example, “satellte” needs to be revised into “satellite”.

Minor revision of the English writing is needed.

Author Response

The point-to-point reply are appended in the upload Response to reviewer #1 file.

Author Response File: Author Response.pdf

Reviewer 2 Report

Optimized Ni-, Co-, Mn- Oxides Anchored on Graphite Plate for Highly Efficient Overall Water Splitting.

1.       The abstract should be carefully revised to highlight the novelty.

2.      The English language of the manuscript should be improved. Many long sentences could be clearer to read.

3.       Authors reported Ni- or Co- doped MnO, Ni- or Mn- doped Co3O4 will show better catalytic activity for water splitting. Co2.1Mn0.9O4 exhibited the best performances than other oxides/mixtures. Elaborate with explanations. How, high valent Mn demonstrate excellent activity?

4.       The effect of host dopant can be studied with following references:

doi.org/10.1016/j.est.2021.103674, doi.org/10.1016/j.jechem.2021.05.002

5.       Literature review for metal oxide based electrocatalyst is still lacking. Following reference can be added: doi.org/10.1016/j.jallcom.2023.170678, doi.org/10.1016/j.jallcom.2023.170678

6.      The author mentioned in introduction that Co2.1Mn0.9O4 electrocatalyst exhibits excellent HER performance because Mn introduced Co3O4 to regulate the energy of hydrolytic dissociation and proton bonding. And what is the source of Co2.1Mn0.9O4 being the real active site in the OER process and having this high catalytic activity of OER?

7.       The authors should discuss in detail in the XPS analysis section, how the charge is redistributed between the interfaces of dopants and Co3O4? Correlate with HER/OER activity.

The English language of the manuscript should be improved. Many long sentences could be clearer to read.

Author Response

The point-to-point reply are appended in the upload Response to reviewer #2 file.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

it can be accept for publication.

Author Response

Dear Reviewer,

Thank you very much for your comments on the manuscript, title: Optimized Ni-, Co-, Mn- Oxides Anchored on Graphite Plate for Highly Efficient Overall Water Splitting. We appreciate the time and effort that you dedicated to the manuscript. According to your comments, we have carefully checked and corrected the whole text, assure that the introduction, references, research design, methods, results and conclusions are reasonable and accurate, all the spelling and grammar errors are tried our best to avoid in the revised manuscript. We are grateful that your comments are very helpful to improve the quality of the manuscript.