Advances in Hydrolysis of Magnesium and Alloys: A Conceptual Review on Parameters Optimization for Sustainable Hydrogen Production
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThis review distinctly emphasizes magnesium hydrolysis as a viable technique for hydrogen production, consistent with circular economy concepts through the incorporation of waste reutilization. The topic is interesting and within the scope of Metals. The percent match (26%) with the previous works is OK, the number of references is acceptable as well. However, the manuscript requires some revisions before it can be proceeded further.
The manuscript is poorly formatted, i.e. the continuous line numbering is missing, the style and size of font is not correct and change at some places, some parts are highlighted for no apparent reason. Please, improve the presentation style.
Abstract, it should be “layer, which limits hydrogen release”
Beginning of introduction, why past tense is being used instead of the present tense?
Introduction: are the presented enthalpies the standard enthalpies? Also, those reactions should be described in more detailed way. For example, what is their mechanism? Is it one step reaction? Is there a TS?
The dissociation constants (both K1 and K2) for Mg(OH)2 should be presented and discussed.
The effect of temperature on the magnesium hydrolysis should be discussed in more detailed way.
Also, the Authors should focus on the role of the product of this reaction, magnesium hydroxide. What is it further used for? As a medication? Is it utilized any other way?
Figure 1, please add a figure showing cumulative number of works. Also, are those numbers from Scopus or Google Scholar or other database?
The authors should describe the objects of this review (MgH2, Mg(OH)2) in more detailed way-are they solids? What about their polymorphism?
Page 7 and other places as well, it should be H2 not H2. Also, at multiple places the Authors forgot to use the subscripts when presenting the chemical formulas. Please read the manuscript carefully one more time.
The Authors should add another figure, a scheme, presenting the approaches used to increase the efficiency of the hydrolysis. The pros and cons of those approaches should be summarized.
What about the approaches in which the insoluble magnesium salts are being obtained? I.e. carbonate, phosphate?
The Authors should present the methodology behind this review. What databases have been chosen? What were the inclusion/exclusion criteria for the articles presented?
Author Response
We thank the reviewers for their very helpful comments, which helped us greatly to improve the manuscript.
All is in the enclosed file
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe article has already been reviewed, and therefore, it is an updated version of the same.
I see some problems that prevent its publication, even though it has already been reviewed. I will divide them into major and minor issues.
Major problems:
The title does not indicate that it is a conceptual review. My suggestion is: Advances in Hydrolysis of Magnesium and Alloys: A Conceptual Review on Parameters Optimization for Sustainable Hydrogen Production.
The article does not have a purpose. It is just a sequence of topics that do not follow a model. Who is this review for? Who can benefit from this review? I suggest building a conceptual map (or a tree-like strucuture or hierachical conceptual structure) based on a preliminary and quick literature review. Then, proceed with an in-depth review of each branch of the conceptual map. In the introduction, you must demonstrate that there is a research gap, formulate a research question, and indicate how the articles that comprised the preliminary review and the in-depth review were collected. Provide keywords and use accessible databases, such as Scopus and WoS, not the ones mentioned in Figure 1. In the worst-case scenario, compare the search already done with new searches in international databases already mentioned and observe if there are any significant differences. Perhaps using the PRISMA protocol would be a good idea.
Inform clearly and extensively who is interested in this review. Which stakeholders and industries may benefit from your review?
Without formalizing a purpose and informing a method, the review loses value and is less interesting to a top journal's global audience.
Minor problems:
The abstract is long and does not inform how the articles for the review were selected or who is interested.
Remove captions within the figures as they are redundant with the external ones.
Captions should be short (up to 8 words). The explanatory text should be in the body of the article.
Whenever possible, insert mathematical models and inform the R2 in the curves presented (e.g., Figure 2). For example, Figures 4 and 5 could explore how doping and temperature, respectively, influence the exponentiation coefficient of the model, assuming that exponential models explain the influence. Curves with three dimensions could be accompanied by a spatial figure (e.g., Figure 7).
Number all equations and refer to them by number in the text.
The conclusion should return to the purpose of the article and list the research findings. Finally, it should discuss the implications, i.e., which industries can gain what from the findings.
Author Response
We thank the reviewers for their very helpful comments, which helped us greatly to improve the manuscript.
All is in the enclosed file
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsThe Authors have revised and improved their work, making current version acceptable for publication.
Reviewer 2 Report
Comments and Suggestions for AuthorsOk, the authors have satisfactorily addressed most issues or provided satisfactory rebuttals.
