Hydrolyzed Forms of Cellulose and Its Metal Composites for Hydrogen Generation: An Experimental and Theoretical Investigation
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsHevy to read text written from chemists to chemists, not contribute to understanding reaction mechanisms supporting reaction kinetics.
General remarks:
Interesting thematics important for transition period toward decarbonisation.
Text is complicated and heavy to understand, but certainly written from chemist to chemist not to an engineer.
English language can be improved while about 85 % of overall score measured.
No line numbering, no page numbering exists, such a text is heavy to review.
Detail remarks:
- Page 1, section 1, Line “for the future due to its high energy content(141.86kJg-1 ) compared to gasoline (47.50kJg-1)”, word energy content is not technically correct, one should use energy value or calorific value or HHV, to be exact (Higher Heating Value). Separate word content from parentheses. Maybe some volume comparison could be instructive as H2 molecule is light and small.
- Page 2, last paragraph; authors explain use of metals for generation of hydrogen from cellulosic biomass, but not explain the form and function of metal; catalyst, reactant?
- Page 3, section 2.2., it is just declared metal is added to the solution; it is important to tell the form of metal (powder).
- Page 4, first line, some word separation, missing after point.
- Page 4, first paragraph, in the explanation of the principle of gas measurements was not mentioned measuring a cumulative volume of gas evolved.
- Page 4 and 5, indices in graph are not explained (area of peak?).
- Page 7, table1, table should be aligned accordingly.
- Page 8, fig 6, a measurement of H2 volume should be assigned as cumulative.
- Conclusion, pretty short and mechanical without a vision or view toward revealing a reaction mechanism which only lead to understanding of reactions kinetics behind.
References seem to be relevant and extensive enough, their specific content is not checked.
Comments on the Quality of English LanguageLanguage can be improved.
Author Response
Authors' response is attached.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for Authors
Hydrolyzed forms of cellulose and its metal composites for hydrogen generation: An experimental and theoretical investigation.
The study conducted by the authors involved both experimental and theoretical investigations on hydrogen generation. The focus was on the hydrolysis of microcrystalline cellulose (MCC) treated in various media, including deionized water and sodium hydroxide. Additionally, the authors examined the hydrogen generation potential of MCC functionalized with magnesium (MCC Mg), titanium (MCC Ti), and niobium (MCC Nb).
Authors need to revise the manuscript considering all the comments.
Comments
· This low hydrogen yield observed due to the treatment of MCC with aqueous NaOH indicates the inhibition of hydrogen production by NaOH ( aq )--- what might be the reason for inhibition of hydrogen production by NaOH.
· However, the treatment of MCC with aqueous urea resulted in the generation of 35 mL of hydrogen over 3000 seconds---- What is the crystallinity of the MCC after all the treatments that led to reduced hydrogen values in the MCC?
· What is the hydrogen conversion efficiency observed in this study.
· The results reveal that the hydrogen yields are approximately 34 mL, 37 mL, and 45 mL over 3000 seconds for MCC Mg, MCC Ti and MCC Nb, respectively, where the volume of hydrogen gas generat ed by MCC Nb composite mixture is slightly higher than the one generated by MCC treated with H2O (40 mL)---- Try to connect the result with of SEM with hydrogen generation – Interpretation of the results are needed.
· The destruction of the hydrogen bonding makes the hydroxyl groups in cellulose available for hydrolysis--- Does this give a greater degree of hydrolysis?
· These results reveal that NaOH inhibits the hydrolysis of MCC, thus leading to a drop in the hydrogen yield of ball milled MCC as showed Fig.7--- Please offer more details on the specific mechanism by which NaOH inhibits hydrolysis.
Author Response
Authors' response is attached.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Comments and Suggestions for AuthorsHydrolyzed forms of cellulose and its metal composites for hydrogen generation: An experimental and theoretical investigation.
Authors
Omar Faye
Inimfon A. Udoetok
Jerzy A. Szpunar
Lee D. Wilson
I have reviewed the author's response to the comments and find that the revisions made are relevant. With these significant changes, the manuscript may be considered for publication.
