Hydrogen Storage Properties of a New Ti-V-Cr-Zr-Nb High Entropy Alloy

Round 1

Reviewer 1 Report

The paper is written in a professional manner. It contains all necessary sections of the peer-review paper. The topic is sound and important. The research in material science related to  the design of novel alloys for hydrogen storage is in the mainstream research. 

I have just one comment. I think it would be valuable to expand section Introduction and present hydrogen research in a bit broader context of EU policy. Especially, in France hydrogen can be produced in the future using heat from nuclear power plants of new generation, e. g. Height Temperature Rectors. This is a novel trend, which can be indicated in the paper. Some references about HTR, which can be cited:

http://www.nukleonika.pl/www/back/full/vol66_2021/v66n4p133f.pdf

https://doi.org/10.1016/j.anucene.2017.03.039

Author Response

We thank the reviewers for the encouraging comments and positive feedbacks.

However, hydrogen production, whatever the method, is outside the scope of the present manuscript. The only mention to hydrogen production is in the introduction but in a very general statement: “As an energy carrier, hydrogen needs to be produced, transported, stored, and finally used in practical applications. Among all steps, hydrogen storage is considered a bottleneck for further development of hydrogen-based economy. Hydrogen can be stored in three different ways: as compressed gas at high pressure, as cryogenic liquid at very low temperature and in solid-state materials....”

In this framework, the authors believe there is no reason to select one mode of hydrogen production then another in the context of this very broad sentence that has the only motivation to highlight that storage is a critical hindrance to further development of hydrogen economy. Consequently, we consider that the proposed citations are outside the scope of the manuscript.

Reviewer 2 Report

Authors reporte the synthesis, the physicochemical and the hydrogen sorption properties 8
of a novel bcc high entropy alloy Ti0.30V0.25Cr0.10Zr0.10Nb0.25. Authors show that at room temperature the alloy absorbs  rapidly hydrogen reaching a capacity of 2.0 H/M (3.0 wt.%) and forming a dihydride with fcc structure, as confirmed by both synchrotron X-ray diffraction and neutron diffraction.

The paper is worth of publishing in present form.

Author Response

We are thankful to the reviewer for the detailed reading of our manuscript and the very positive comments provided.

Reviewer 3 Report

The manuscript presents a complete structural characterization of the novel high entropy alloy TiVCrZrNb under hydrogen uptake and characterizes its hydrogen storage capabilities using ex-situ and in-situ hydrogenated temperature dependent syncgrotron x-ray diffraction and neutron diffraction, as well as chemical microscopic analysis.

The study is well construed and clearly presented.

Author Response

We are thankful to the reviewer for the detailed reading of our manuscript and for the encouraging comments and positive feedbacks.