Ethanol Electrooxidation on Phase- and Morphology-Controlled Ni(OH)2 Microspheres
Round 1
Reviewer 1 Report
The paper presents a communication on ethanol electrooxidation for fuel cells. The catalyst, i.e., morphologically controlled Ni(OH)2 microspheres, is promising in terms of sustainability and promises to allow insight on the mechanism of this ni catalyst. Maybe in conclusions the authors should explain better how they intend to continue the investigation.
Experimental part is accurately performed and clearly presented.
There is one point that is nor clear to me, The authors correctly defined EOR as ethanol oxidation reaction- However, a number of times they used OER, without any definition. I suppose it has the same meaning. If so, please, use a single abbreviation. If not, please, define it.
Author Response
Response to Reviewer #1’s comments.
Maybe in conclusions the authors should explain better how they intend to continue the investigation.
Reply: Slightly edited the part of the conclusion with the discussion on further study starting from line 284.
There is one point that is nor clear to me, The authors correctly defined EOR as ethanol oxidation reaction- However, a number of times they used OER, without any definition. I suppose it has the same meaning. If so, please, use a single abbreviation. If not, please, define it.
Reply: OER defined as oxygen evolution reaction at first mention in line 140.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
This manuscript describes the electrooxidation of ethanol on Ni(OH)2 catalyst prepared by solvothermal method. Although the outcome of this study is not very exciting, as suggested by the authors, the study proposes to add to the collective apprehension on Ni based catalysts for ethanol reforming applications. Therefore I suggest that this paper can be accepted to Catalysts, however, the authors need to work a little bit on a few minor points. Here are my comments:
-Abstract
-EOR explain abbreviation on abstract.
-Introduction
-Line 67: “In the past, it has been suggested that EOR activity catalyzed by Ni is dependent on the Ni(OH)2/NiOOH redox pair, hence, these occur at overpotentials much higher than those reported for Pd or Pt.” I saw that you explained this later in the results section starting from line 139. But I think you should still be more specific and explanatory here in the introduction and justify your statement with references.
-Results
-The results section starts with a new introduction for explaining the alpha- and beta-Ni(OH)2. I believe this part can be moved to the introduction and expanded there.
-Line 78: It is written that the synthesis procedure is detailed in SI. This is given on section 3.1 and I did not see anything about synthesis procedure in SI. Please correct it.
-Line 85: JCPDS database is now called is ICDD. The PDF card no must be different, please update them.
-Table S2 could be moved to the main text as it provides important summary of the samples. In this way, the reader does not have to go back and forth between the main text and the SI.
-Line 120: Here is the first time a figure in SI is cross-referenced. Why weren’t the two tables and figures in the SI mentioned in the main manuscript? If they are not relevant, please delete them from the SI. Also, for Figure S3, mention that A-G refers to the samples in the caption.
-3.1 synthesis: the details of supplier and purity is missing for the nickel precursor.
-3.2 degree sign is missing for the scan rate.
-Line84: there are two dots.
Line 207: ‘at elevated’ written twice.
-Conclusion
The conclusion is very long and in fact the last paragraph seems more like a discussion which could be incorporated with the last paragraph starting at line 203.
Author Response
Response to Reviewer #2’s comments.
EOR explain abbreviation on abstract.
Reply: EOR acronym removed from abstract.
Line 67: “In the past, it has been suggested that EOR activity catalyzed by Ni is dependent on the Ni(OH)2/NiOOH redox pair, hence, these occur at overpotentials much higher than those reported for Pd or Pt.” I saw that you explained this later in the results section starting from line 139. But I think you should still be more specific and explanatory here in the introduction and justify your statement with references.
Reply: We have added the explanation and citations in line 73.
The results section starts with a new introduction for explaining the alpha- and beta-Ni(OH)2. I believe this part can be moved to the introduction and expanded there.
Reply: We have transferred discussion on Ni(OH)2 structure to introduction starting from line 74.
Line 78: It is written that the synthesis procedure is detailed in SI. This is given on section 3.1 and I did not see anything about synthesis procedure in SI. Please correct it.
Reply: We have corrected callback to synthesis procedure in line 86.
Line 85: JCPDS database is now called is ICDD. The PDF card no must be different, please update them.
Reply: We have updated JCPDS to ICDD in line 89.
Table S2 could be moved to the main text as it provides important summary of the samples. In this way, the reader does not have to go back and forth between the main text and the SI.
Line 120: Here is the first time a figure in SI is cross-referenced. Why weren’t the two tables and figures in the SI mentioned in the main manuscript? If they are not relevant, please delete them from the SI. Also, for Figure S3, mention that A-G refers to the samples in the caption.
Reply: Table of summary of morphologies now included in main text as Table 1. We have referenced Figures S1 and S2 as examples of the measurements in the table in line 116.
3.1 synthesis: the details of supplier and purity is missing for the nickel precursor.
Reply: We have added the supplier and purity of nickel precursor in line 226 (now Chemicals and Materials section).
3.2 degree sign is missing for the scan rate.
Reply: We have added the missing degree symbol in line 242.
Line84: there are two dots.
Line 207: ‘at elevated’ written twice.
Reply: We have corrected the above typographical errors.
The conclusion is very long and in fact the last paragraph seems more like a discussion which could be incorporated with the last paragraph starting at line 203.
Reply: We have transferred part of conclusion to results and discussion at line 214 to shorten the conclusion.
Author Response File: Author Response.pdf
Reviewer 3 Report
The paper is well developed and scientifically investigated.
It can be summarized better the results achieved using few highlights.
I suggest few minor revisions, they are reported below:
- The graphical abstract should be added
- a nomenclature list can be added considering also SI unit of measure
- please try to reduce acronyms in the abstract
- carbon deposition phenomena was considered even if I suggest a deep investigation section for ethanol vs FC
- at which operating temperature these tests were conducted
- I suggest to move section 3 before section 2, generally, Material and methods appears before the results section
- section of materials needs that all details should be added
- there are few grammar errors
- quality of fig.1 should be improved, 1.f seems blurriness
- pag. 3 line 110 Is it possible to find a reference?
Author Response
Response to Reviewer #3’s comments.
The graphical abstract should be added
Reply: Graphical Abstract has been submitted to MDPI-Catalysts. We believe it will be included in the online version by the editors.
a nomenclature list can be added considering also SI unit of measure
Reply: We believe that there is no need for a nomenclature list as the acronyms have now been defined within the main text and the units of measure used are all in SI.
please try to reduce acronyms in the abstract
Reply: Most of the acronyms have been removed and the few that remain have been defined within the abstract.
carbon deposition phenomena was considered even if I suggest a deep investigation section for ethanol vs FC
Reply: We believe that within the temperature and potential range there is no carbon deposition phenomena that would occur and is beyond the intended scope of our research.
at which operating temperature these tests were conducted
Reply: We have specified the temperature at which tests were conducted at line 269.
I suggest to move section 3 before section 2, generally, Material and methods appears before the results section
Reply: The order of section is as recommended by MDPI-Catalysts. We believe that retaining it will be consistent with the journal’s format.
section of materials needs that all details should be added
Reply: We have added the Chemicals and Materials section added at line 225.
there are few grammar errors
Reply: We have further corrected grammatical errors we have spotted in our proofreading.
quality of fig.1 should be improved, 1.f seems blurriness
Reply: This is the clearest possible for this sample with the magnification used to show features. A larger version is available but we believe that it does not merit a separate figure from the rest of the figures in Figure 1.
pag. 3 line 110 Is it possible to find a reference?
Reply: Added reference to Page 3 line 112.
Author Response File: Author Response.pdf
