Picosecond Lifetime Hot Electrons in TiO2 Nanoparticles for High Catalytic Activity
Round 1
Reviewer 1 Report
The content of the paper fits more to the topic of the physic and I am not sure that it brings significant information for the target group of the readers of the journal “Catalysts”.
Although this is true that in chapter 3.1 the authors mentioned that the creation of the excited states having a very long lifetime in the conduction band is the crucial for high photocatalytic activity of NPs, there is not any recommendation within the paper how to design new catalysts (photocatalysts) with higher efficiency. Although the authors highlight the fact that the defect structure is better with respect to catalytic (photocatalytic) performance, the clear message about this issue is not visible from the paper. The comparison of the observed results for the samples no. 29, 82, 53 and 84 with real photocatalytic activity of these samples is necessary to demonstrate and clearly comment.
Other comments:
- Authors should correct the English, check and correct the typos (“utile” vs. “rutile”, ...)
- Authors should better describe the TiO2 NPs used – anatase vs, rutile. 100nm – crystallite size or the size of the particles?
- Why the authors mentioned I, In (page 4, line 109) and did not use this variables further in the figures and text?
- What is the main difference between the samples no. 29, 82, 53 and 84 ? They all should be TiO2, the samples are not described in chapter 4.
- Why authors mentioned in Conclusion that high catalysis of gold nanoparticles smaller than 10 nm will be caused by the quantization of the electronic states although their paper is focused on TiO2?
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The authors investigated the lifetime of hot electrons in TiO2 nanoparticles using PEEM and discuss the reason of high photocatalytic activity of the nanoparticles. The experimental methods and results are new and very interesting. I think this paper is worth publishing.
However, there are some mistypes in conclusion section.
Page 15 L16
Original ...are excited by SH pule to the Eg sate
--> ...are excited by SH pulse to the Eg state
Author Response
Response to reviewer 2
The authors investigated the lifetime of hot electrons in TiO2 nanoparticles using PEEM and discuss the reason of high photocatalytic activity of the nanoparticles. The experimental methods and results are new and very interesting. I think this paper is worth publishing.
However, there are some mistypes in conclusion section.
Page 15 L16
Original ...are excited by SH pule to the Eg sate
--> ...are excited by SH pulse to the Eg state
Response
Thank you very much for your evaluation and for pointing the mistype.
The revised manuscript was English edited by MDPI, this journal.
Reviewer 3 Report
The manuscript by Li et. al describes the investigations of picosecond lifetime hot electrons in TiO2 nanoparticles. However, I do not understand the structure of the work, where is the theoretical reasoning, and where is the experimental work of the authors. The authors write about the electronic properties of titanium dioxide nanoparticles. In this case, it is not said anywhere how the synthesis of titanium dioxide was carried out, data on their characterization and properties were not provided. In the title of the article it is written about "high catalytic activity", but in the text catalytic activity is not mentioned anywhere. In conclusion, I believe that this article has a very indirect relation to the catalysis and cannot be published in the "Catalysts" journal.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Before the publishing of the paper I would recommend again to check the text. In my opinion it is a pity if the authors are not aware about the style - there are some imperfections like page 2, line 50 " … hot electrons.[20] ...", should be " … hot electrons [20]. …" etc.
Author Response
Dear Reviewer 1
>Before the publishing of the paper I would recommend again to check the text. In my opinion it is a pity if the authors are not aware about the style - there are some imperfections like page 2, line 50 " … hot electrons.[20] ...", should be " … hot electrons [20]. …" etc.
Thank you very much for pointing this error.
We are sorry, but we are poor at finding careless errors.
The certificate of the English editing by the MDPI English service is attached. Our careless errors were corrected, as you confirmed in the revised manuscript.
Because we know the style and because we did not make this error at other places, we failed to notice the company corrected the error on line 50 pointed by the reviewer.
By carefully reading the manuscript again, we found some other errors. For example, we noticed we failed to add “d” after “evaluate” on line 300. We noticed “c” should be a capital letter “C” for Coulomb on line 328. We also noticed the space before the reference numbers were missing in many places.
We tried our best to find careless errors and they are corrected as seen in the re-revised manuscript. We hope there are no other careless errors.
We thank you again for pointing the error on line 50.
Author Response File: Author Response.pdf
Reviewer 3 Report
I’m satisfied with the answers
Author Response
>I’m satisfied with the answers
We thank you very much.
