Comparing the Performance of Supported Ru Nanocatalysts Prepared by Chemical Reduction of RuCl3 and Thermal Decomposition of Ru3(CO)12 in the Sunlight-Powered Sabatier Reaction
, Jelle Rohlfs 4, Francesc Sastre 4, Pau MartÃnez Molina 4, Nicole Meulendijks 4, Marcel A. Verheijen 5,6, An-Sofie Kelchtermans 1,2,3, Ken Elen 1,2,3, An Hardy 1,2,3, Marlies K. Van Bael 1,2,3,* and Pascal Buskens 1,4,*Round 1
Reviewer 1 Report
This is an interesting story on the construction of nano-photo-catalyst showing how to improve the preparation of supported Ru nanocatalysts for sunlight-powered Sabatier reaction. This text decisively deserves publication. The title reaction is known; however, the authors developed a novel method for preparing the catalyst. Instead of supporting Ru nanoparticles on γ-Al2O3 by impregnation of γ-Al2O3 with Ru3(CO)12 and subsequent thermal decomposition, they used chemical reduction of RuCl3 as a precursor. They compared the resulting properties and catalytic activity of the preparation, finding no differences in the catalytic behavior of the catalysts. Accordingly, a novel procedure for catalyst preparation is the real innovation. In my opinion, this is enough to ensure the interest of the research audience engaged in sunlight technologies. In catalyst research, we need novel experimental data and functional and material properties to be measured, published, and shared. Authors should indicate this aspect of the investigations justifying a potential interest of the audience, compare: [J. Mol. Sci. 2021, 22(10), 5176; https://doi.org/10.3390/ijms22105176]. Some critics can also refer to Figure 4, where the Authors show the results for two preparation methods but the reader (at least the Reviewer) cannot identify this in Figure? Publish with minor changes.Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
The paper submitted Daria Burova et al. deals with a subject on which there has been growing interest in recent years: catalytic methanation of CO2 boosted by sunlight. Though the work is written and organized satisfactorily, it needs some reinforcement. In particular the characterization of the materials is rather poor. How do the authors identify and quantify the metal Ru? TEM analysis has to be supported by at least XRD and TPR with H2 consumption to discern between Ru NPs and RuOx particles (refer to 10.1021/acscatal.8b04710)
Some minor tips
- Introduction line 63: I would add some consideration about the shape of the catalyst that is fundamental for industrial application: take a glance to the papers and add as refs https://doi.org/10.1016/j.ijhydene.2020.01.120; https://doi.org/10.1016/j.cattod.2019.01.042 )
- Results and discussion, line 129-132 belong to experimental section
In conclusion, the paper can be published only after major revisions.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
The manuscript presents a clear and simple question that is clearly addressed and answered by the work presented. In particular, it has been demonstrated that chemical reduction procedure for silica and alumina materials impregnated with RuCl3 results in a heterogeneous catalytic system for Sabatier reaction. The activities found are comparable to materials generated by thermal decomposition of Ru3(CO)12. The results are interesting and deserve publication in Catalysts. I only suggest some minor points to be considered:
- Some control experiments to discard a possible role of adsorbed hydride species should be considered.
- Figures 3 and 4 should be improved. Specially, the content of figure 4 do not macth with the information in the caption.
Author Response
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Author Response File: Author Response.pdf
Reviewer 4 Report
Authors describe the development of photomethanation catalyst.
The experiments are seems to be well organized.
Few things to mention,
1. [The particle size of Stöber SiO2 and its distribution were characterized via dynamic 280 light scattering (DLS), using a Brookhaven ZetaPals machine]
Authors need to describe more in detail (dispersed in water in XX pH or in dry condition)
2. In catalysis experiments, chemicals are analyzed by GC. Author need to explain how to quantify the chemicals (calibration curves for each chemicals)
In addition, I recommend that the figures of several representative GC chromatograph data should be included in Figure 3, and 4. Other figures of GC chromatograph of catalytic experiments are needed in supplementary information.
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
I thank the authors for the exhaustive explanation regarding the reducibility of ruthenium. The work was revised according to the suggestions
