Cu and Cu-Fe Bi-Metal Nanoparticles Encapsulated in Hollow S-1 Zeolite for Reverse Water Gas Shift Reaction

Round 1

Reviewer 1 Report

This is a very interesting piece of work in which a novel catalyst is deployed in a reaction of great interest nowadays. The article is clear and well-written. Conclusions are based upon facts an data, without inconsistent speculations.

However, some points need clarification,

1 - How external diffusion limitations were eliminated in the catalyst evaluation?

2 - The isotherm for the CuFe0.5@S catalysts presents two hysteresis loops, one at low pressures. How do the authors explain the existence of such second loop?

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

1. Equilibrium data can be added to the result.

2. The preparation of different catalysts is confusing for section 2.2.2 and 2.2.3, Please check the real name.

3. The CO2-TPD is not reasonable because the baseline at the beginning is still very high. 30 min Ar treatment at 30 min may not be enough for the purge, especially for zeolite with a higher surface area. Longer Ar time or higher temperature was suggested.

4. What is the reason for CO2/H2 at 3 instead of 1?

5. For H2-TPR, there should be peaks of FeOx reduction at >300 C. Please check. 

6. Please check the Xco2 and Sco calculation equations.

7. Some sentences need evidence, from more detailed investigation or from citations, such as "which is resulting from the significant generation of strong basic sites. "

8. The Fe should be in the oxidized state during the reaction as the catalyst was only reduced at 300 C. It is recommended to use "FeOx species instead of "Fe species" in this work. In addition, this catalyst should not be named as  the "bimetallic".  

There are many parts need to improve such as There should be x-axis title in Fig 1a, the unit of 2θ should be °.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

1.Please check Sco equation again, "12vol%H2,/36vol%CO2, 52vol%" . Where is Fco, in, and why is Fco2, out

2. "Cu-S and CuFe0.5@S catalysts were synthesized by a dissolution-recrystallization (DR) method" in 3.2.3 seems not right.

Subscription and space between number and unit should be noted and improved.

Author Response

Please see the attachment.