Improvement of NH3-SCR Performance by Exposing Different Active Components in a VCeMn/Ti Catalytic System
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsIn this paper, the authors systematically demonstrate the roles of different active components over the VCeMn/Ti mixed oxide catalysts and improve the NH3-SCR performance. The paper is well-organized and provides solid evidence to prove their findings. This paper can be taken in consideration for acceptance after a Minor revision. Comments are provided below.
Comment 1: As shown in Figure 2, SO2 co-feeding alone can lead to a NOx conversion drop by 23% (78% - 55%), and H2O + SO2 co-feeding can lead to a NOx conversion by 19% (55% - 36%), and these two values have no big difference. Therefore, the inhibition mechanism for these two co-feeding might have no big difference. More discussion for Figure 2 is recommended to provide, since Figure 2 provides convincing information in the main text.
Comment 2: For discussion from Line 142 to 146, Scherrer equation can be used to estimate the oxide particle size, then the comparison can be more straightforward. For discussion from Line 149 to 152, did the authors collect EDX mapping to reflect the elemental uniformity (Fig S2)? For discussion from Line 157 to 161, did authors get pore volume and surface area for spent catalysts to compare the structure stability among selected catalysts (in Table 1)?
Comment 3: For discussion from Line 179 to 182, the intensity of the band at ~ 960 cm-1 was too weak compared to the rest of main peaks (at 168~450, 685 cm-1), it is hard to assign the enhanced activity to this band. Thus, Raman analysis can be placed into supporting information. In addition, since NH3-TPD , O2-TPD, H2-TPR are more convincing data, the sequence to present these data can be adjusted (put Raman data after TPD/TPD data).
Comment 4: For Figure 7(d), the signal/noise ratio is too low, and it can be moved into supporting information. For Figure 10, how to explain the peak shift with the ramping temperature for the band at 1232~1292 cm-1? By comparison, this peak shift was not observed in Figure 11 after NH3 co-feeding.
Author Response
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Reviewer 2 Report
Comments and Suggestions for AuthorsThe presented work touches on an important area of research and is directed from an interesting angle - from the point of view of understanding the influence of the order of deposition of components on the observed catalytyc effects. It is interesting and useful. The presented results are important, and the conclusions are sufficiently substantiated. At the same time, I have a few comments that I ask you to consider:
- The axis caption in Figure 2 "time (mine)" must be corrected to have the correct units of measurement
- According to the data presented in Figure 3, the rutile phase is not shown in the P25 sample, although it must be present there
- I have doubts about the correctness of decoding and dividing vanadium states into several. The noises are too strong to show the existence of other states besides V5+ on Figure 7(d). Therefore, either describe why the signal line is curved or depict the signal with a single peak corresponding to V5+
- Figure 8: еhere may be an illusion that Ce4+ turns into Ce3+ by itself without any external factors and interactions, according to this scheme. But it's not like that. The scheme needs to be clarified
- It is extremely inconvenient for me, as a reader, to search for the entire section 3 in the supporting information. At least some of the information can be given in the main text of the article to create greater comfort for the reader when reading and understanding the conditions of the process
Comments on the Quality of English Language- A large number of typos and incorrect use of words that need to be corrected - double-check the English.
- Duplicateв sentence (page 2 line 55)
Author Response
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Reviewer 3 Report
Comments and Suggestions for AuthorsIn this work the authors studied the effect of impregnation of V and CeMn on TiO2 for the NH3-SCR.
The sentence from lines 84 to 86, cannot be supported with the results displayed in Figure 1(a) because the catalysts do not have significantly different catalytic performance.
In the abstract it is mentioned that "The V/CeMn/Ti catalysts exhibited exceptional catalytic efficiency and strong tolerance to SO2 during the SCR process" and this is not demonstrated in the work. Figure 2 shows that all catalysts present a certain level of deactivation and this performance is not recuperated when de SO2 is eliminated from the reaction conditions. The best catalyst, V/CeMn/Ti, lost almost half its performance in SO2 presence, and it looks like this desactivacion is not reversible. Then, why did the authors mention this in the abstract?
I recommend that for Figure 4 the authors inform in the figure legend what corresponds to each wavenumber mentioned in the figure.
- The reduction onset temperatures of the catalysts in Figure 6b are similar for VCeMn/Ti and Ve/CeMn/Ti, and lower than CeMn/V/Ti, and not as mentioned by the authors in lines 221 to 224.
I recommend that the information in Materials and Methods and Catalyst Characterization (Experimental Section) given in the supplementary material should be added to the article.
Could the authors provide more information on the TiO2 P25 used in this work?
I recommend the publication of this paper after the authors make the suggested changes.
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
Comments and Suggestions for AuthorsThe changes and modifications are correct, so I suggest that the document be published in its current form.
