Ru/Attapulgite as an Efficient and Low-Cost Ammonia Decomposition Catalyst

Round 1

Reviewer 1 Report

In this paper, the authors have investigated a novel Ru-based catalyst for ammonia decomposition in which nano-Ru particles are supported on a naturally abundant mineral fiber, attapulgite. The structure of naturally occurring and calcinated attapulgite powder was analyzed by XRD analysis. Testing the catalyst against ammonia decomposition revealed its good catalytic performance, achieving 100% conversion at 600°C, while the Ru metal content is only 1%. The latter is crucial as Ru is a very expensive material. 

The design of the experiment and organization of the manuscript are well done, and I suggest publication with only minor revisions:

1.      The authors stated "Although the catalytic activity of 1Ru/ATP is lower than some other Ru-based catalysts listed in Table 4, most of these catalysts were loaded with higher Ru content". However in the introduction, they mention, "Karakaya et al. developed a ternary ceramic-oxide compound 66 (BaO)2(CaO)(Al2O3), which achieved a cracking efficiency of 100% above 500°C after the impregnation of 1 wt.% Ru". This result is not present in Table 4.(?)

2.      Since it is known that the efficiency of Ru catalysts is very structure-sensitive, some discussion on structure of 1Ru/ATP catalyst and its efficiency would be welcome.

3.      It is interesting that the 1Ru/ATP catalyst exhibited good stability with low degradation rates, considering Ru catalysts are prone to hydrogen poisoning, poisoning by impurities, and so on. Is there some explanation for this stability?

4.      Recently a very interesting paper on this topic appeared in Nature communications journal (Fang, H., Wu, S., Ayvali, T. et al. Dispersed surface Ru ensembles on MgO(111) for catalytic ammonia decomposition. Nat Commun 14, 647 (2023). https://doi.org/10.1038/s41467-023-36339-w) I suggest citing this article. 

Author Response

Please see the attached file.

Author Response File: Author Response.pdf

Reviewer 2 Report

In the current manuscript Teng et al., discussed about the fabrication of Ru/Attapulgite catalyst for the low-cost ammonia decomposition. This paper required major revision before further consideration. Following are the points need to be addressed.

1.     In the abstract, the authors mentioned the difference in activity because of the calcination before and after the loading of Ru. However the activity was not mentioned in the manuscript.

2.     Why the authors have chosen only 1wt%.  justify it.

3.     Quantification of products is not there in the manuscript. I suggest the authors should provide the complete details of the quantification procedure.

4.     Authors studied electrochemical performance with external H2 and NH3 cracked H2 and reported the data. The NH3 cracked H2 gave low activity compared to Pure H2. I suggest the authors perform additional experiments with dilution of N2 in H2 and justify the answer. 

Minor editing of English language required

Author Response

Please see the attached file.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

All comments are answered properly by the authors. Now the paper can be published in its present form.

English is fine.