Furfural Hydrogenation on Modified Niobia
, Daniel Delgado 2, Nicola Scotti 3, Claudio Evangelisti 4, José M. López Nieto 2 and Laura Prati 1,*Round 1
Reviewer 1 Report
The manuscript topic is not under the scope of this journal. The work is based on catalytic materials and development of furfural hydrogenation. I recommend authors to submit to more appropriate journals such as Catalysts, Materials or molecules.
Author Response
The Special Issue we were invited to regards the support effect in liquid phase reaction so I think the paper fits perfectly with the topic.
Reviewer 2 Report
The authors have presented the experimental evidence but have missed to do include conclusions after detailed data analysis. Including these would increase the scientific soundness of the manuscript.
1) Particle size distribution from TEM/STEM images should be included to understand the difference between different samples and also, as TEM is local technique, detailed particle size distribution is necessary to claim anything about average particle size of the sample.
2) Particle size can also be calculated from XRD and can be used to further support the claims from TEM.
Author Response
Following the reviewer’s suggestion, histograms of particle size distribution were included in the manuscript (new Fig. 4). In order to have a representative particle size distribution at least 500 particles located in different grains of the support were counted. As appeared from the histograms reported in the new Fig. 4 the three niobium oxide showed very similar particle size distributions (0.5 - 2 nm) and mean diameters (1.1 – 1.2 nm).
Reviewer 3 Report
Review for “Furfural hydrogenation on modified Niobia”
In the manuscript, the authors doped W and Ti in Nb2O5 to improve the performance of Pt-Nb2O5 system for the hydrogenation of furfural. The author successfully synthesized W/Ti-doped Nb2O5 materials and incorporated with Pt nanoparticles. The author, based on the catalysis results, concluded that the Lewis acid sites on the doped Pt/W-Nb2O5 have a strong contribution to the surface acidity which future influences the furfural reaction rate and product selectivity. There are some minor questions need to be addressed before published in Applied Sciences.
1. Typo in keywords: hydrogenation.
2. Page 3, line 97 to 100 and line 108 to 111, the words are almost identical. Suggest rewrite and only highlight the differences.
3. Figure 4b, for the Raman spectra, authors described the Raman feature changing upon W and Ti doping. The phenomena are very distinguishable, but the authors did not provide any insides for the Raman shifts. Why the dopants would introduce a Raman shift in the opposite direction? Could the author provide the explanation? Also, the FWHM varies for three cases. For the Ti, there is a large background slope. Please explain.
4. In Table 2, the BET measurement results are not mentioned until line 302 page 9. Please reorganize.
5. In Table 3, the second column has not been mentioned or defined anywhere in the text. Please address.
6. In Figure 5, line c, there is a peak around 1520 cm-1. Could the authors provide interpretation?
7. For Figure 8, the distribution differences between Pt/W and Pt is relatively small in term of FE and FEA generation. Could the author provide some information on the error bars?
8. In the conclusion section, between line 325 and line 330, there are intensive data interpretations, which is not expected in the conclusion of the paper. Please address.
Author Response
In the manuscript, the authors doped W and Ti in Nb2O5 to improve the performance of Pt-Nb2O5 system for the hydrogenation of furfural. The author successfully synthesized W/Ti-doped Nb2O5 materials and incorporated with Pt nanoparticles. The author, based on the catalysis results, concluded that the Lewis acid sites on the doped Pt/W-Nb2O5 have a strong contribution to the surface acidity which future influences the furfural reaction rate and product selectivity. There are some minor questions need to be addressed before published in Applied Sciences.
1. Typo in keywords: hydrogenation.
Typo has been corrected
2. Page 3, line 97 to 100 and line 108 to 111, the words are almost identical. Suggest rewrite and only highlight the differences.
The paragraph has been modified in order to avoid repetitions.
3. Figure 4b, for the Raman spectra, authors described the Raman feature changing upon W and Ti doping. The phenomena are very distinguishable, but the authors did not provide any insides for the Raman shifts. Why the dopants would introduce a Raman shift in the opposite direction? Could the author provide the explanation? Also, the FWHM varies for three cases. For the Ti, there is a large background slope. Please explain.
The following explanation has been inserted into the text:” The shift can be explained in terms of the specific weight of the dopant elements, i.e. heavier species (like W6+) will shift the bands to higher frequencies, while lighter dopants (like Ti4+) would shift the bands to lower frequencies. In addition, doped supports show broader Raman signals, due to a higher disordered degree (as observed in XRD patterns) [44]”
4. In Table 2, the BET measurement results are not mentioned until line 302 page 9. Please reorganize.
BET analysis has been added in Section 3.1 (page 7, line 232)
5. In Table 3, the second column has not been mentioned or defined anywhere in the text. Please address.
The column has been deleted
6. In Figure 5, line c, there is a peak around 1520 cm-1. Could the authors provide interpretation?
The intensity of the pyridine bands on the 1% Pt/Nb90Ti10O5 sample is very low because of its small acid site concentration. The broad hump around 1520 cm-1 could not be assigned to a specific signal. Rather it is due to the experimental noise after the subtraction of the spectrum of the support without the probe molecule to the one with pyridine collected at 150 °C. Moreover, in the open literature there is not any correlation with a peak in this specific spectral region for pyridine adsorption/desorption experiments.
7. For Figure 8, the distribution differences between Pt/W and Pt is relatively small in term of FE and FEA generation. Could the author provide some information on the error bars?
Product analyses have been performed using GC as mentioned in the experimental section. In order to assure product analysis reproducibility, some analysis have been repeated twice and in all the occasions the error between each measurement was less than 1 %. In addition, in order to assure reaction reproducibility, the reaction performed with Pt/W-Nb2O5 was repeated twice. The results show differences in activity and product distribution lower than 3 % in all the cases.
8. In the conclusion section, between line 325 and line 330, there are intensive data interpretations, which is not expected in the conclusion of the paper. Please address.
We agree with the Reviewer’s comment and transfer this part into the Discussion Section.
Reviewer 4 Report
In this work, Pt supported on three different niobia-based materials were prepared and tested for furfural hydrogenation. The W and Ti dopants were found to modify the surface acidity of the support and thus the catalytic activity and selectivity of the furfural hydrogenation. The catalysts were well characterized by XRD, SEM, TEM, Raman, and FTIR. This is an interesting study and the manuscript is well written. I recommend publication of this manuscript after minor revisions.
1. The resolution of Figure 4 can be improved.
2. The title of the manuscript is not given in Supplementary Information.
3. Figures S2 to S5 in Supplementary Information are not related to the work reported in the manuscript.
Author Response
In this work, Pt supported on three different niobia-based materials were prepared and tested for furfural hydrogenation. The W and Ti dopants were found to modify the surface acidity of the support and thus the catalytic activity and selectivity of the furfural hydrogenation. The catalysts were well characterized by XRD, SEM, TEM, Raman, and FTIR. This is an interesting study and the manuscript is well written. I recommend publication of this manuscript after minor revisions.
1. The resolution of Figure 4 can be improved.
Image quality has been improved.
2. The title of the manuscript is not given in Supplementary Information.
Title has been added to the Supplementary Information
3. Figures S2 to S5 in Supplementary Information are not related to the work reported in the manuscript.
Figures S2 to S5 have been deleted.
