Deactivation and Regeneration for the SO₂-Poisoning of a Cu-SSZ-13 Catalyst in the NH₃-SCR Reaction

Round 1

Reviewer 1 Report

The manuscript is very well presented. A wide range of appropriate characterisation methods is applied. The results are very clearly stated and those are correlated well with already known literature. The relevant results are also cross-correlated between each technique.

There are a few aspects that will have to be changed/clarify prior to publishing.

Line 67 -  It needs to be taken into account that XRD has some limitations. Firstly, lab-based XRD requires at least 5% of certain phase to be detected. Secondly, Cu oxides, if formed, could be present in the amorphous form. And that would not be detected by XRD. Other means of spectroscopy such as, for example, X-ray absorption spectroscopy would have to be used to confirm this observation.

Line 117 -  Based on the visual inspection of SEM images presented in the manuscript the cube-shaped crystalinity is present for all the samples with quite small distortion.

Line 130 - more evidence is needed to confirm the presence of copper sulfate

Figure 5 - it is worth to check if the same colours were used for each Cu fraction. For the plots R-650 and R-700 it looks like the Cu+ and Cu2+ at ca. 950 eV swapped the positions.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

Understanding of deactivation of SCR catalyst is important for its practical applications. Therefore the studies in this area are valuable and worth to perform.

In this paper Authors studied deactivation and regeneration of the commercial catalyst under different conditions using physicochemical methods, such as XRD, SEM, XPS and absorption/desorption measurements. By collection of results it was possible to characterize structural changes of the catalyst and its active sites. In particular, an effect of SO2 on the catalyst regeneration was shown.

The studies were well planned and correctly performed, the obtained results were clearly presented. The paper can be published without any changes.

Author Response

Thanks to the reviewer for giving us so much wonderful and constructive suggestion.

Reviewer 3 Report

The authors report on a study on the SO2-poisoning and regeneration process of a commercially available Cu-SSZ-13 catalyst for the NH3-SCR reaction.

The manuscript is well written and readable in all its parts. The authors have characterized the materials with different techniques and discuss the results by citing the relevant literature.

Experimental part contains all the details necessary to reproduce the experiments.

Conclusions are consistent with result discussion.

Author Response

Thanks to the reviewer for giving us so much wonderful and constructive suggestion.

Reviewer 4 Report

The manuscript (catalysts-598806) entitled “Deactivation and regeneration for the SO₂-poisoning of a Cu-SSZ-13 catalyst in the NH₃-SCR reaction” describes an interesting and consisted work concerning the deactivation and regeneration of a commercial NH₃-SCR catalyst. Fresh, deactivated, and regenerated at various temperatures catalyst samples were characterized by N₂-physisorption, XRD, XPS, SEM-EDX, NH₃-TPD and H₂-TPR and evaluated for the title reaction. The conclusions are well supported by the results and the work is worth to be published after careful editing because the existence of several syntax errors makes the text difficult for the readers.

The authors can find some specific comments bellow:

Line 37: “A problem, however, SO₂ is an inevitable compound ….” should be changed to “A problem, however, is that SO₂ is an inevitable compound ….” Line 44: “… is caused by SO₂ interacts ….” should be changed to “… is caused by SO₂ interaction ….” Line 46: “… catalysis deactivation …” should be changed to “… catalyst deactivation …” Line 48: “… The catalysis activity …” should be changed to “… The catalytic activity …” Line 50: “… were studied, …” should be changed to “… was studied, …” Line 87: “… regenerated …” should be changed to “… regeneration …” Line 103: “… of catalysts gone after …” should be changed to “…of catalysts was gone after …” Line 106: “… Wang [18].” should be changed to “… Shen et al. [18].” Line 114: the words “… crystal surface structure and …” should be omitted. Line 115: “… cube-shaped crystals …” should be changed to “… cube-shaped grains …” Line 115: “… were evident.” should be changed to “… are evident.” Line 124: “… of investigation samples were …” should be changed to “… of studied samples are …” Line 127: “Wang et al. [26] …” should be changed to “Shen et al. [26] …”. Reference to a scientific article should be made by writing the name of the first author. Authors should carefully review the references in their text in accordance with this rule. Line 128: “… decompose …” should be changed to “… decomposed …” Lines 128-130: The text “Since sulfur species can be completely removed when temperature reached 700 °C, it was reasonably believed that there was copper sulfate over our sample because of the copper sulfate with higher thermal stability.” should be rephrased. It is unclear. Line 140: “… locating …” should be changed to “… located …” Line 144: “… was displayed …” should be changed to “… are displayed …” Lines 149-150: The phrase “This maybe …//… by XRD.” Should be rephrased. Line 156: “… demonstrated …” should be changed to “… demonstrating …” Line 164: the word “… that …” should be omitted. Lines 194-196: It seems better to write “In this study, we interpreted the first peak (α) from the fresh sample at lower temperature as an indication of the reduction of isolated Cu²⁺ located in different cationic sites to Cu⁺” Line 199: perhaps it is better to write “…and Cu⁺ species produced by Cu²⁺ ions reduction [34-37].” instead of “…and Cu⁺ species reduced by Cu²⁺ ions [34-37].” Line 205: Please, change “… groups during …” to “… groups created during …” Line 212: Please, change “… hydrothermal …” to “… hydrothermally …” Line 238: Please, change “It is worth noted that the catalyst …” to “It is worth noting that the catalyst …” Line 239: Please, change “oxide” to “oxidize” Line241: Please, change “… bind to more ammonia …” to “… bind more ammonia …” Line 282: Please change “… active …” to “… activity …” Lines 290-291: Please, rephrase the phrase “This phenomenon …//… from XPS.” Line 303-304: Please, rephrase the phrase “… and the irreversible …//… reactions.” Lines 310-313: Please, rephrase the text “As shown in Figure 2 …//… of F-Cu. Line 311: Please, change “… morphological …” to “… morphology …”

Author Response

Please see the attachment

Author Response File: Author Response.pdf