Catalyst for the Generation of OH Radicals in Advanced Electrochemical Oxidation Processes: Present and Future Perspectives

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript is a timely well organized review.  It is in general written well. I recommend authors add SrTiO3 to their analysis.  The conclusion and perspective part is very weak, for this article, the authors should try to expand this section a bit: especially on where the field is going, I have not felt like there is any perspective while the section title mentions perspective. 

Comments on the Quality of English Language

English is satisfactory. 

Author Response

See attached document.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

This work provided a comprehensive review on catalysts for the generation of OH radicals in Advanced Electrochemical Oxidation Processes. Overall, this manuscript has a very well organized structure. The state-of-the-art has been thoroughly reviewed in an insightful way. This work is likely to impact the further development of Advanced Electrochemical Oxidation Processes. Based on these considerations, I would like to recommend publication at Catalysts, however, before that, some minor issues need to be properly resolved. Please address the below detailed comments in order to further improve the quality of the manuscript.

1. The last paragraph of Introduction needs some revision. Building on the context provided earlier, this paragraph should highlight the key issues that will be covered in this review contribution and indicate what implications this review can have.

2. Related works on AOPs can be referenced in the Introduction section (e.g., ACS Sustain Chem Eng, 2022, DOI: 10.1021/acssuschemeng.1c07605).

3. Line 134, the authors mentioned that “synthesis, structural properties, surface area, stability, scalability and selectivity of materials are crucial for this process”. However, some of these parameters were not or less explored in the following main text, such as “surface area” and “selectivity”.

4. Recent works on electrocatalysis are suggested to be included in the relevant sections (InfoMat, 2024, DOI: 10.1002/inf2.12608).

5. In conclusion section, the authors discussed that “To test a new material, the laboratory scale and pilot scale must be considered at the same time”. Please reconsider this statement. If the new material does not perform well in a lab setting, does it still need to be considered for pilot scale testing?

6. The section “6. Conclusions and perspectives” should be further enriched with the authors’ own perspectives. Additional referencing might be needed to aid such discussion.

7. In sections 3-5, more figures should be cited to aid the discussion of AOP cases. While the focus of this review is on AOPs, very few figures on AOPs were cited.

Author Response

See attached document.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The paper provides a comprehensive review of catalysts used in Advanced Electrochemical Oxidation Processes (EAOPs) for the generation of hydroxyl radicals (OH•) and active chlorine species. It discusses the mechanisms of reactive species generation, emphasizing both homogeneous and heterogeneous advanced oxidation processes (AOPs). The authors delve into the electrochemical generation of OH• radicals under dark conditions and photon irradiation, highlighting the role of various electrode materials such as boron-doped diamond (BDD), tin dioxide (SnO2), and titanium dioxide (TiO2). The paper emphasizes recent trends in hybrid synthesis methods that combine these techniques to create novel catalysts like MoS2-NHCS and doped TiO2 variants. It also discusses electronic modifications of materials through element doping, heterojunction formation, defect engineering, and strong-interfacial interactions to enhance catalyst performance. Case studies are presented to illustrate the application of these catalysts in laboratory and pilot-scale EAOPs. The paper highlights the need for standardized evaluation parameters and the importance of catalyst durability in real-world applications.

 

I’m supportive of the publication of this paper, if the authors can address my following comments: 

1. Synthesis Methods: The paper mentions various synthesis methods for catalysts but does not delve deeply into how these methods mechanistically affect catalyst properties and performance. How do the different synthesis methods influence the physicochemical properties of the catalysts? Are there specific advantages or limitations associated with each method that impact their suitability for EAOPs?

2. The paper acknowledges the challenges in scaling up from laboratory to pilot scale but does not provide concrete strategies to address these issues. What are the key factors limiting the scalability of these catalysts? Are there ongoing efforts or proposed solutions to overcome these challenges in pilot or industrial settings? Are there any challenges on the engineering side?

Author Response

See attached document.

Author Response File: Author Response.pdf