Single-Atom Transition Metal Photocatalysts for Hydrogen Evolution Reactions

Round 1

Reviewer 1 Report

The work presents a good review on the single atom transition metal photocatalysts for hydrogen evolution reactions. I think it can be publishable after solving the following issues.

1. It is suggested to include a schematic for the fundamental mechanism of photocatalyst decorated with single atom transition metals in the first part.

2. As HER is just a half reaction of water splitting, it should also give some discussion on the counter reactions, such as OER, some related studies (10.1039/d2ta04914g; 10.1016/j.cej.2021.131004) are recommend for discussion in the outlook section.

3. There are some clerical mistakes on the spelling words. The figure background should remove the watermark. In addition, the authors should check the refences carefully to meet the journal requirements, such as some journal names are not abbriviated (Ref 41).

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

In this manuscript, HER on single-atom transition metal photocatalysts is reviewed, including the approach to synthesis, usually used materials for the photocatalysis, and current performance. However, there are several places could be modified or corrected before its publication. I would like to suggest a minor revision for this manuscript. My specific suggestions are as follow:

1.     The single-atom transition metal photocatalysts should be clearly defined in the manuscript. In this version, the catalysts including clusters, small nano particles, and single atoms are discussed. It makes the reader feels confusing. The size of the catalysts would significantly impact the HER mechanism on the catalysts surface. Therefore, the HER mechanism on single-atom transition metal catalysts also should be clearly stated in the introduction part of the review.

2.     The ordinate name in Figure 5 should be checked. It should be “H2 evolution amount” rather than “H2 evolution rate”.

3.     Comparation between the single-atom catalysts and other kinds of catalysts could be included to make the review be more comprehensive. The difference between the host materials, single-atom metal could be listed in the table to make the review be clearer.

4.     In line 76, is the abbreviation DOS correct?

5.     In line 50, please add the specific value for the conduction band close to the H+/H2 reduction level.

6.     The sentence between line 39 and line 42 should be clearly stated.

7.     In line 86, it should be mentioned which kinds of metal atoms that are usually used in photocatalyst systems.

8.     Figure 3 could be corrected to make it clearer. In this version, there are two “electrodeposition” in this Figure, making it confusing.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Concerns have been solved for accepted now.