Influence of Nanoconfinement on the Hydrogen Release Processes from Sodium Alanate
Round 1
Reviewer 1 Report
The aim of the paper, i.e. the influence of nanoconfinement on the H2 release processes from NaAlH4, is quite interesting. Authors measured the H2 release from bulk, purely nanoconfined, and intermediate NaAlH4 at different temperature ramp rates, and determined the characteristic parameters for each hydrogen release process. Moreover, the authors presented and discussed the impact of nanoconfinement on the H2 release processes from NaAlH4 and the limitations of each process in case of bulk and nanoconfined NaAlH4.
The abstract summarize the work. The purpose of the study is clearly outlined and the findings of prior work are well discussed. There are no errors in logic or experimental procedure. The authors accurately explain how the data were collected. There is sufficient information that the experiment can be reproduced. All topics are well presented and discussed. The summary and conclusions are sound and justified. All presented figures are good quality and they prove their point. The paper is written in good English. The manuscript is easily readable concerning language, style and presentation. The references are appropriate and up to date.
Author Response
Thank You!
Reviewer 2 Report
The manuscript by the authors studies the nano-confinement effect on the H2 release from sodium alanate. Thanks for putting together nice work. It was a pleasure reading your work.
The work is concise, ordered and can be accepted after few minor corrections.
1) What could be the effect of the porosity (micro, and meso pores) in high surface area carbon? Using a 2D graphene, CNT can further influence the H2 release?
2) What is the purity of NaAlH4 used for deposition process?
3) Details about H2 release (ml/min per g NaAlH4) can be derived from the experiment and the data should be added.
4) Rate of Heat flow data from DSC experiment can give some insight.
Author Response
Please see the attachment.
Author Response File: 
Author Response.docx
Reviewer 3 Report
Please give more information in the materials and methods section. State the supplier of all materials used, and give some details about the porous carbon. What was the water content of THF, was any chemicals purified before use? Was inert atmosphere used throughout the experiments?
Moreover, maybe some examples of raw data should be provided as supporting information (selected traces at different delta T - by the way, is not the designation delta T a bit misleading for rate of temperature change?).
In the introduction the authors state that high pressure H2 tanks present an inherent hazard; however, will not sodium alanate react violently with water, and does this not constitute a severe safety risk?
Is the kinetic models employed by the authors really appropriate for this type of complex processes - especially with regards to the kinetic trapping of H2 mentioned by the authors?
Finally, I think the authors should provide a more explicit description of what is novel in this manuscript, compared to earlier published studies by the authors and others. What do we learn by reading the manuscript that has not been published before? The effect of nanostructured sodium alanate is well known, as explained by the authors themeselves.
On page 6, line 200 the expression "Ea-s" is given, and on page 7 line 207 "T-s" I could not find that the meaing of the -s was explained anywhere.
Author Response
Please see the attachments.
Author Response File: Author Response.docx
Round 2
Reviewer 3 Report
The clarifications and additional explanations are satisfactory.
