The Synthesis of a Pt/SAPO-11 Composite with Trace Pt Loading and Its Catalytic Application in n-Heptane Hydroisomerization
, Yanhong Cui 1, Huijie Gao 2, Yisi Zhou 3, Wei Zhang 1, Yanhua Suo 1 and Yingjun Wang 1,*Round 1
Reviewer 1 Report
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Reviewer 2 Report
My comments/suggestions:
a)the text from line 67 to line 104 is a repetition of the previous text
b) eliminate the comment at line 158: Tables should....
c) avoid to use B acid center instead of Bronsted acid center
d) some figures (like 4 and 5) seem to me less significant ; put them in SI
e) the claim at line 209 seems to me not correct or you must explain the behaviour of 0.5% Pt/SAPO11. also in the conclusion you need to underline this point
f) what do you mean with the expression "animation diagram" in Scheme 1?
g) figures S2-S7 show some parts as totally black and are useless. May you improve the quality of these imagines
h) please correct the tex of formulas 4 and 5 at page 13
i) please insert any comment under the figures in SI
j) are all your self-citations really useful? if yes you must explain the difference and improvements of the present manuscript over the state of art and your previous researches
I have already answered to this question in the comments to the authors
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Reviewer 3 Report
The design of Pt/SAPO catalysts for hydroisomerization is widely discussed in the literature. A simple Pt/SAPO keyword search gives about 400 references for 2022-2023. Here are just a few of them [Pt Single Atom-Anchored CeOx/SAPO-11 for Highly Efficient Hydroisomerization of n-Heptane. Hao Qin , Nengjie Feng , Quan Lv , Hui Wan * , Guofeng Guan // Fuel Processing Technology
Volume 241, March 2023, 107604https://doi.org/10.1016/j.fuproc.2022.107604
(The main results: 0.05%Pt1@CeOx/SAPO-11 proves highly efficient with a TOF per Pt site of 9511 h−1. Metal-acid balance and intimacy effect of hydroisomerization still work for SACs. Ptδ+ (0 < δ < 2) is the true active metal species of the Pt1@CeOx/SAPO-11catalyst);
Pt@SAPO-11 bifunctional catalysts with spatial architecture constructed via a seed-directed solvent-free strategy for n-dodecane hydroisomerization. Yangchun Tan, Wenjing Hu, Jia Cheng , Hao Zhao, Yanyan Du, Heliang Yao, Jiusheng Li//Microporous and Mesoporous Materials
Volume 330, January 2022, 111607https://doi.org/10.1016/j.micromeso.2021.111607;
Effects of Pt site distributions on the catalytic performance of Pt/SAPO-11 for n-dodecane hydroisomerization Guang Lva,b , Congxin Wanga , Kebin Chic , Hao Liua , Ping Wanga,b , Huaijun Maa , Wei Qua , Zhijian Tian//Catalysis Today Volume 316, 15 October 2018, Pages 43-50 https://doi.org/10.1016/j.cattod.2018.04.07].
It follows from these examples that the authors have poor knowledge of the literature in this area. And obtaining new original results on this topic is a difficult task. The results presented are one specific example of a variety of Pt/SAPO catalysts. If the authors manage to show the advantages of their developments over known data, then the article can be published after major revision. This is not visible in the current version.
In addition, the article is very poorly designed. Just look at the introduction, which consists of two repeating parts (lines 35-71 and 72-104). The purpose of the work is not formulated and the abstract does not show specific results of the work. The Pt loading range chosen by the authors can hardly be called trace. At best, it could only be discussed as a reduced Pt content. For example, low loaded (10-2 -10-3%) Pt catalysts on zeolites and alumina with synergistic action were highly efficient in the CO oxidation [
Total and preferential CO oxidation on low-loaded Pt-HZSM-5 zeolites modified using laser electrodispersion Russ Chem Bull 72 (2023) 1518. https://doi.org/10.1007/s11172-023-3930-y;
Role of surface coverage of alumina with Pt nanoparticles deposited by laser electrodispersion in catalytic CO oxidation //Applied Surface Science 536, 2021, 147656 https://doi.org/10.1016/j.apsusc.2020.147656]. It would be better to talk about the extreme dependence of catalytic properties on the Pt loading in the article title. In this case, some novelty will become visible. But then it is necessary to discuss in more detail the reasons for the extreme dependence. According to the data presented in the work, this cannot be done, since the TEM and XPS data are given only for the best catalyst with 0.5Pt loading. Besides, statistical processing of data to analyze particle size distribution should be given.
There are also many specific comments on the XPS data:
Pt4f and P4d spectra (Fig. S11 in Supporting Information) were not fitted in a reliable and self-consistent way.
1. For each Pt species the ratio of Pt4f7/2 to Pt4f5/2 peak areas should be close to the theoretical value of 4:3. This is not the case for Pt0 and Pt4+ species.
2. The Al2p peak seems to be too narrow. The FWHMs of Al2p and Si2p peaks in alumosilico compounds are typically close. The authors should use larger FWHM of the Al2p peak. It will also help to achieve more reliable Pt4f7/2 to Pt4f5/2 peak area ratios.
3. The reliable fitting of the overlapped Al2p and Pt4f spectra was earlier described by Golubina et al. in Applied Surface Science. 2021. V. 536. P. 147656 (DOI: 10.1016/j.apsusc.2020.147656).
4. The Pt4d5/2 line overlaps with the loss structure of the C1s line, with the latter probably dominating in the spectrum. Therefore, the fitting presented in the Fig. S11(b) is not reliable. Additionally, the presence of the Pt2+ component in the Pt4d5/2 spectrum contradicts the absence of this component in the Pt4f spectrum. Because of the low intensity of the Pt4d line and its overlapping with the loss structure of the C1s spectrum it should be recommend omitting the Pt4d spectrum.
It would be important to compare the surface (XPS) and bulk (calculated or analyzed?) Pt content.
Some more remarks:
Figure 3b. Comment d=0.477
Figure 4. Apparently, the isotherms are shifted along the Y axis for clarity? This must be said. The negative slope of some sorption isotherms and the large number of significant figures in Table 1 also look strange. With such values ​​of specific surfaces, they can all be considered the same within the measurement error. Figure 5. SAOP in the Fig.? Line 207 - The catalytic activity – What is this? Just a conversion, without taking into account different Pt content? Line 248 - The XRD of 0.5Pt/SAPO-11 was almost the same – This is only about SAPO? And what about the Pt state?
254 -2.7. Mechanism of n-heptane hydroisomerization over xPt/SAPO-11
What's new can be added on the results of this work?
338 n-Heptane was fed into the reactor – And what about hydrogen?
347 - xPt/SAPO-11 catalysts had good catalytic performance of n-heptane isomerization – It can be concluded in comparison with known catalysts;
354-356 - The mechanism of xPt/SAPO-11 catalysts for n-heptane hydroisomerization was further inferred, and increasing the coordination between Pt metal sites and B acid sites was the key to enhancing the conversion of n-heptane and selectivity toward n-heptane isomers. This conclusion is not justified by the results of the work.
Comments for author File: Comments.pdf
There are a lot of mistakes and typos, English needs to be improved
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Round 2
Reviewer 1 Report
Kindly proof read the manuscript
Kindly proof read the manuscript
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Reviewer 3 Report
I don't agree with the article title.
0.5%Pd is not a trace loading.
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