Facile Preparation of a Novel Bi2WO6/Calcined Mussel Shell Composite Photocatalyst with Enhanced Photocatalytic Performance
Round 1
Reviewer 1 Report
The submitted manuscript is reporting about a facile solvothermal route for fabrication of hierarchical Bi2WO6/calcined mussel shell (BWO/CMS) composites used for degradation of model pollutant under visible light illumination from waste water. The presented work is attractive to the readership and worth to be publicized.
I have a question about the role of the CMS in the composite when it is illuminated with visible light. So the generated charge carriers from BWO do not transfer to the CMS? The author also state that CMS can contain metals. Have you measure the amount of metals in the CMS and the type of the metals?
My next question is about the specific surface area of pure BWO. You report only the value for the composite. Maybe a high specific surface area BWO would have a higher catalytic activity?
Author Response
The submitted manuscript is reporting about a facile solvothermal route for fabrication of hierarchical Bi2WO6/calcined mussel shell (BWO/CMS) composites used for degradation of model pollutant under visible light illumination from waste water. The presented work is attractive to the readership and worth to be publicized.
I have a question about the role of the CMS in the composite when it is illuminated with visible light. So the generated charge carriers from BWO do not transfer to the CMS? The author also state that CMS can contain metals. Have you measure the amount of metals in the CMS and the type of the metals?
Answer: Thank you for your helpful suggestions. Actually, according to our results, the higher catalytic performance of BWO/CMS is due to the formation of fascinating hierarchical structures with numerous exposed edges, and open transfer pathways, which can create more open space and reactive sites for photocatalytic reaction. Such favorable characteristics enable BWO/CMS to efficiently degrade organic pollutants (e.g. rhodamine B (RhB), methylene blue (MB), Tetracycline hydrochloride (TC)) under visible light. Additionally, we did not examine the the amount of metals in the CMS due to the impact of COVID-19 and the short time given for this revision. However, other reports have demonstrated the existence of some metals in the CMS (Environ Res 2020, 188, 109831).
My next question is about the specific surface area of pure BWO. You report only the value for the composite. Maybe a high specific surface area BWO would have a higher catalytic activity?
Answer: Thank you for your helpful suggestions. N2 adsorption-desorption isotherms were further utilized to determine the Brunauer-Emmett-Teller (BET) surface area of the samples. As exhibited in Figure 3, CMS/BWO-2 exhibits the type IV isotherms, demonstrating the porous structure, which is verified by the pore distribution plots. As anticipated, the hierarchical structure endows CMS/BWO-2 with high BET surface area (36.87 cm2 g-1). For comparison, the BET surface areas of CMS and Bi2WO6 are found to be 10.64 and 34.29 m2g-1, respectively (Table S1). In general, high surface area is favorable to efficient adsorption and photocatalytic activity.
In contrast to the stacked Bi2WO6, CMS/BWO-2 has numerous exposed edges, and open transfer pathways, which can create more open space and reactive sites for photocatalytic reaction. Such favorable characteristics enable CMS/BWO to efficiently degrade organic pollutants (e.g. rhodamine B (RhB), methylene blue (MB), Tetracycline hydrochloride (TC)) under visible light.
Reviewer 2 Report
This is a high-quality work about a topic, which still interests many researchers. It does have the advantage of using waste material as well. The experimental work was performed professionally applying a large scale of relevant instrumentation. Overall, the manuscript is written well, a final English check is only required. In my view the work can be accepted for publication.
Author Response
This is a high-quality work about a topic, which still interests many researchers. It does have the advantage of using waste material as well. The experimental work was performed professionally applying a large scale of relevant instrumentation. Overall, the manuscript is written well, a final English check is only required. In my view the work can be accepted for publication.
Answer: Thank you for your positive comments.
