A Review of Photocatalytic Materials for Urban NOx Remediation

Round 1

Reviewer 1 Report

A very interesting review in the field of NOx photocatalysis in the lab and on site. Well documented, well written.
Here you can find some small comments:

Line 70-73: It's a long sentence, so perhaps put a dot after it 'year' ?

Line 83: You mention other abatement methods. Which ones? or give a reference?

Line 96-101: It's a long sentence !

Line 106: Figure 1 : change H+ with h+ to avoid confusion with atomic hydrogen? and also change OH with OH^.

Line 181: Did you have the opportunity to see the patent side as well?

Line 216: P25 ---> I think there is a confusion, it is the opposite. anatase 75% and rutile 25%. See ref: Journal of Catalysis 203, 82–86 (2001)

Line 248: "humidity has been shown to reduce RE significantly.." Since the photocatalytic reaction involves OH radicals coming from H2O, is there a minimum value of relative humidity for the reaction to take place?

Line 274: "yielding an NO2 RE of -20% at 2000 ppb..." -20% negative value? What does this mean?

 

Author Response

Please see attachment. I also emailled an editted Graphical abstract.

Author Response File: Author Response.pdf

Reviewer 2 Report

The reviewed paper written by H.S. Russell and co-authors deals with a complex review of application of photocatalytic denitrification processes. Authors has focused on both, either on laboratory studies and also field studies in which photocatalytic materials was applied on various buildings materials. Although semiconductor photocatalysis represents promising method to improve air quality, from this paper it follows basics limitation for practical large scale application (active surface deactivation, NO₂ production, various level of UV intensity and humidity). Authors did lot a hard work to summarize data from many actual studies, which were reflected in relevant conclusions and recommendation. According to my opinion this paper can be published without further changes.

Author Response

Response to Reviewer 2 Comments:

Dear reviewer, 

Thank you very much for your comments and recognition of our work.

Best Regards, 

Hugo Russell

 

Reviewer 3 Report

In this manuscript, Dr. Russell et al. reported the current state of the art of photocatalytic oxidation materials designed for NOx abatement in the urban environment. The manuscript is well-organized, and the authors highlighted the most potential methods and new testing standards for NOx abatement. I would recommend that it be accepted by “Catalysts” after the authors address the following minor suggestions:

• I would recommend that the author summarize the impact of physical parameters on the equations. In the literature, how is it calculated? This section should include and discuss photonic efficiencies and quantum yields. For example, the following manuscript could be cited, which discusses physical parameters in detail. https://doi.org/10.1016/j.jhazmat.2011.11.041
• Similarly, in the modeling section, authors could present some designed NOx abatement models with images.
• The illustrations and equations are conspicuously missing from this manuscript. The impact of this review article would be increased if the authors supported their discussion with attractive images and relevant equations. Otherwise, the classifications and summaries at the end of each section are accurate.
• I suggest that authors include the most recent manuscripts in the material improvement sections. In general, there is no comparison of the materials that used for NOx abatement which should be strengthened in this section. The manuscripts listed below could be cited.

https://doi.org/10.1021/jp5108069

https://doi.org/10.1016/j.apcatb.2021.119974

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

The authors have comprehensively responded to all of the comments, and I recommend that this manuscript be accepted for publication in Catalysts.