Improvement of Chemical Stability of Perovskite Nanocrystals as a Photoelectrochemical Catalyst for Hydrogen Evolution Reaction
Round 1
Reviewer 1 Report
The author submitted a paper titled "Improvement of Chemical Stability of Perovskite Nanocrystals as a Photoelectrochemical Catalyst for Hydrogen Evolution Reaction" for publication.This paper introduces the method of "obtaining core-shell perovskite nanocrystals by two different types of silane through two cross-linking reactions to improve chemical stability and conductivity". This work is both interesting and reasonable. Therefore, I suggest that the following issues be clarified and published in Catalysts magazine.
1. In the introduction, the author should provide detailed references to the literature on the preparation of perovskite through crosslinking reaction to demonstrate this effect.
2. In XRD testing, the author described "In order to enhance the resistance of the perovskite NCs to water, it was necessary to increase the thickness of the shell. To achieve this, we added the amount of APTES during the synthesis process." However, it is best for the author to explain how the thickness of the core shell changes with the content of APTES.
3. The title of the article is "Improvement of Chemical Stability of Perovskite Nanocrystals as a Photoelectrochemical Catalyst for Hydrogen Evolution Reaction", and it is recommended to evaluate the stability of hydrogen evolution.
4. What are the advantages of the cross-linked perovskite/SiO2 nanocrystals provided in this experiment compared to the perovskite nanocrystals produced through a two-step cross-linking reaction?
5. The format of captions in the text should be unified.
Author Response
Please find attached our point-by-point response to the reviewer's comments in a separate file.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The authors reported a two-time cross-linking approach to prepare core-shell perovskite nanocrystals (NCs) for the application of photoelectrochemical hydrogen evolution reaction (HER). The effects of the amount of APTES and vinyltrimethoxysilane on crystal structures and microstructures, as well as the optical properties were studied. The role of UV exposure in enhancing the secondary cross-linking with the help of photo initiator was also investigated. They claimed the Ag-doped core-shell NCs prepared using this strategy showed the best HER performance than the other three dopants. The whole manuscript was fairly organized. It can be accepted for publication after the following questions/comments are addressed.
1. Why the onset potentials of Cu-, Ni-, and Bi-doped NCs were higher than Ag-doped sample? Brief explanation is needed.
2. The chemical stability was only done in PL measurements. Any stability test in the photoelectrochemical operational conditions?
3. The authors said “…by exposing it to UV light. The aim was to reduce the distance between the NCs and promote more efficient carrier transport.” Any evidence of distance shortening?
4. XRD peak assignments in Figure 1a and Figure 4c have to be double-checked. The positions where the specific planes belong to are different than the literature.
5. It was argued that the lowest onset potential obtained from Ag-doped sample was due to effective band modulation. Did the authors measure UV-vis spectra for bare NCs and Ag-doped NCs to verify the band modulation? The authors also said the effectiveness of this doped sample in promoting the redox reaction was attributed to provision of effective active site. This has to be checked.
6. The authors said “the as-coated film using CsPbBr3/SiO2 NCs with a photo initiator exhibited a new peak at 1710 cm−1, associated with the C=O stretching of the photo initiator.” The peak was observed before or after UV exposure?
7. In the characterization part the authors described SEM, but no SEM image was shown in the main text.
8. How did the authors prepare the working electrode? Which counter electrode and reference electrode were used?
9. Specification of UV lamp needs to be provided.
10. In the conclusion, the authors said the Ni-doped was the best performing one. Wasn’t it Ag-doped?
11. All the reported onset potentials should be corrected to negative values. It’s not appropriate to put the onset potential of Ag-doped sample in the inset unless clearly noted.
12. The full name of “QDs” is needed. The caption in Figure 1 has to be checked, specifically “higher magnitude”. The numbering for conclusion should be 4 instead of 5. In schematic, it was labeled “Vinylsilane” but in the main text it was “Vinyltrimethoxysilane”. The caption in Figure 3 for IPA and ethanol was reversed. In Figure 4b, the title of x-axis should be wavenumber (cm-1).
13. The resolution of all figures has to be improved. Scale bars in TEM image are not visible.
14. It is advised to put each figure after the first descriptive paragraph.
Author Response
Please find attached our point-by-point response to the reviewer's comments in a separate file.
Author Response File: Author Response.pdf
