Surface Plasmon Resonance Induced Photocatalysis in 2D/2D Graphene/g-C3N4 Heterostructure for Enhanced Degradation of Amine-Based Pharmaceuticals under Solar Light Illumination
Round 1
Reviewer 1 Report
This paper reports the Gr/g-C3N4 composite photocatalytic materials by the direct thermal method. The catalytic system with superior activity for visible-light-induced degradation of amine-based pharmaceuticals (Nizatidine and Ranitidine). Under solar light irradiation, the sample with a 5% graphene to g-C3N4 ratio showed higher efficiency for the degradation of amine-based pharmaceutical models. The degradation reached 85% within 20 min only.
I suggest the authors to address the following issues:
1. The abstract is too long and it is suggested that the experimental characterization should be streamlined and the experimental results.
2. In the introduction, the recently development about g-C3N4 based photocatalysts should be summarized e.g., Adv. Powder Mater. 2022, 1, 100021; Materials Today Nano, 2022, 18, 100204; Journal of Colloid and Interface Science, 2022, 605, 320-329.
3. Carefully check the formatting of the images, for example figures 5 and 8 should be aligned with other images.
4. The sample with a 5% graphene to g-C3N4 ratio showed higher efficiency. However, the optimum concentration was not found and I think we should continue to increase the concentration of graphene in order to find the optimum concentration.
5. The discussion of the mechanism of the Gr/g-C3N4 material is rather vague and it is suggested to add a mechanism diagram to visualise it.
6. The degradation experiments in Figure 8a and b do not indicate which catalyst is used.
Author Response
Manuscript Title: Surface plasmon resonance induced photocatalysis in 2D/2D Graphene/g-C3N4 heterostructure for enhanced degradation of amine-based pharmaceuticals under solar light illumination.
Manuscript ID: 2218177
Authors: Faisal Al Marzouqi, Rengaraj Selvaraj*
Reviewers' Comments to Author:
Reviewer: 1
This paper reports the Gr/g-C3N4 composite photocatalytic materials by the direct thermal method. The catalytic system with superior activity for visible-light-induced degradation of amine-based pharmaceuticals (Nizatidine and Ranitidine). Under solar light irradiation, the sample with a 5% graphene to g-C3N4 ratio showed higher efficiency for the degradation of amine-based pharmaceutical models. The degradation reached 85% within 20 min only. I suggest the authors to address the following issues:
Comment 1: The abstract is too long and it is suggested that the experimental characterization should be streamlined and the experimental results?
Reply: Thanks a lot to the reviewer for carefully reading our paper. The abstract has been modified in the new version were the experimental characterization should be streamlined and the experimental results.
Comment 2: In the introduction, the recently development about g-C3N4 based photocatalysts should be summarized e.g., Adv. Powder Mater. 2022, 1, 100021; Materials Today Nano, 2022, 18, 100204; Journal of Colloid and Interface Science, 2022, 605, 320-329
Reply: Many thanks for the reviewer’s kind suggestion, suggested references were consulted and appropriately cited in some sections of the manuscript.
Comment 3: Carefully check the formatting of the images, for example figures 5 and 8 should be aligned with other images.
Reply: The whole manuscript has been modified, and the formatting of the images corrected
Comment 4: The sample with a 5% graphene to g-C3N4 ratio showed higher efficiency. However, the optimum concentration was not found and I think we should continue to increase the concentration of graphene in order to find the optimum concentration
Reply: Reviewer’s suggestion is acknowledged the amount of graphene at 3% and 5% showed not much improvement and that’s why the 5% value selected and upper limits.
Comment 5: The discussion of the mechanism of the Gr/ g-C3N4 material is rather vague and it is suggested to add a mechanism diagram to visualise it.
Reply: Reviewer’s suggestion is acknowledged. The mechanism diagram has been added.
Comment 6: The degradation experiments in Figure 8a and b do not indicate which catalyst is used..
Reply: Thanks a lot to the reviewer for carefully reading our paper. The missing information has been added to the revised manuscript.
We have modified our manuscript based on all reviewers’ comments. We hope that the changes in the revised manuscript would satisfy the reviewers. Finally, we would like to thank all the reviewers and Editors for giving valuable suggestions to improve this paper.
Yours sincerely,
Prof. Rengaraj Selvaraj., Ph.D., FRSC., FICC.,
Professor of Analytical and Environmental Chemistry
Department of Chemistry, College of Science
Sultan Qaboos University
P.O. Box: 36., P.C. 123, Al-Khoudh, Muscat
Sultanate of Oman
E-mail: [email protected]
Tel: 00968-2414 2436
Author Response File: 
Author Response.docx
Reviewer 2 Report
The authors developed a Graphene/g-C3N4 photocatalyst with superior activity for pollutant removal. This work has been well designed and performed. Some modifications are required before publication in this journal. Comments are listed below:
1. Just as other catalytic reactions, photocatalytic reactions need to be normalized with respect to specific surface area of individual samples.
2. More significant advanced photocatalysts should be introduced to keep abreast of the latest research trends. e.g.: Chem. Eng. J., 2023, 455, 140943, Adv. Fiber Mater., 2022, 4, 1620, Separation and Purification Technology, 2023, 304, 122401, Catalysts 2023, 13, 437.
3. The SEM images of C3N4 and Gr should be provided for comparison.
4. The nanofiber-based catalysts show great advantages in the treatment of organic pollutants, e.g., Adv. Fiber Mater., 2022, 4, 1069; Adv. Fiber Mater., 2022, 4, 1278; Adv. Fiber Mater., 2022, 4, 573; Adv. Fiber Mater., 2022, 4, 1595;
5. The transient photocurrent response can also predict the photocatalytic activity. The transient photocurrent responses of all the samples should be measured.
6. Adsorption-desorption tests must be performed before the start photoreaction process. The pollutant adsorption percentage on the samples must be provided and their effects on the photocatalysis need to be discussed.
7. Mineralization tests are missed. What is the process efficiency in the removal of TOC?
8. How about the stability of this material?
Author Response
Manuscript Title: Surface plasmon resonance induced photocatalysis in 2D/2D Graphene/g-C3N4 heterostructure for enhanced degradation of amine-based pharmaceuticals under solar light illumination.
Manuscript ID: 2218177
Authors: Faisal Al Marzouqi, Rengaraj Selvaraj*
Reviewers' Comments to Author:
Reviewer: 2
The authors developed a Graphene/g-C3N4 photocatalyst with superior activity for pollutant removal. This work has been well designed and performed. Some modifications are required before publication in this journal. Comments are listed below:
Comment 1.: Just as other catalytic reactions, photocatalytic reactions need to be normalized with respect to specific surface area of individual samples.?
Reply: Thanks a lot for the best suggestion. In general, the carbon nitride showed low surface area value. However, the main focus of this study was to report the SPR effect were the surface area analysis, and more depth investigation will be conducted in our upcoming work.
Comment 2: More significant advanced photocatalysts should be introduced to keep abreast of the latest research trends. e.g.: Chem. Eng. J., 2023, 455, 140943, Adv. Fiber Mater., 2022, 4, 1620, Separation and Purification Technology, 2023, 304, 122401, Catalysts 2023, 13, 437.
Reply: Many thanks for the reviewer’s kind suggestion, suggested references were consulted and appropriately cited in some sections of the manuscript.
Comment 3.: The SEM images of C3N4 and Gr should be provided for comparison.
Reply: The SEM images were provided for the carbon nitride and both were included in TEM and the section modified
Comment 4: The nanofiber-based catalysts show great advantages in the treatment of organic pollutants, e.g., Adv. Fiber Mater., 2022, 4, 1069; Adv. Fiber Mater., 2022, 4, 1278; Adv. Fiber Mater., 2022, 4, 573; Adv. Fiber Mater., 2022, 4, 1595;
Reply: Many thanks for the reviewer’s kind suggestion, suggested references were consulted and appropriately cited in some sections of the manuscript.
Comment 5: The transient photocurrent response can also predict the photocatalytic activity. The transient photocurrent responses of all the samples should be measured.
Reply: the initial scope of this work is just to discuss the control synthesis of Gr/g-C3N4 with some application. Moreover, the current objective at our lab is to report the physiochemical properties (photocurrent). This will be tested by several analytical techniques and more following up investigation is going on and will be reported in the following work.
Comment 6: Adsorption-desorption tests must be performed before the start photoreaction process. The pollutant adsorption percentage on the samples must be provided and their effects on the photocatalysis need to be discussed.
Reply: Many thanks for the reviewer’s kind suggestion, the adsorption desorption test was added in the corresponding figures (Figures 8 and 9).
Comment 7: Mineralization tests are missed. What is the process efficiency in the removal of TOC.
Reply: Reviewer’s suggestion is acknowledged. Unfortunately, due to some facility limitations, the TOC analysis was not performed, however, it will be included in our future work.
Comment 8: How about the stability of this material.
Reply: Many thanks to the respected reviewer, the initial scope of this work is just to discuss the control synthesis of Gr/g-C3N4 with some application. Moreover, the current objective at our lab is to report the physiochemical properties and stability, and reproducibility along with the total mineralization of the pollutant. This will be tested by several analytical techniques and more following up investigation is going on and will be reported in the following work.
We have modified our manuscript based on all reviewers’ comments. We hope that the changes in the revised manuscript would satisfy the reviewers. Finally, we would like to thank all the reviewers and Editors for giving valuable suggestions to improve this paper.
Yours sincerely,
Prof. Rengaraj Selvaraj., Ph.D., FRSC., FICC.,
Professor of Analytical and Environmental Chemistry
Department of Chemistry, College of Science
Sultan Qaboos University
P.O. Box: 36., P.C. 123, Al-Khoudh, Muscat
Sultanate of Oman
E-mail: [email protected]
Tel: 00968-2414 2436
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
This manuscript can be accepted.
Reviewer 2 Report
After checking the revised version, I think that the authors have well addressed the issues. In this case, this manuscript can be recommended for publication
