Catalytic Hydrodeoxygenation of Solar Energy Produced Bio-Oil in Supercritical Ethanol with Mo2C/CNF Catalysts: Effect of Mo Concentration
, Daniel Torres 1, Esther Frecha 1, Pedro Arcelus-Arrillaga 2, Heidi Isabel Villafán-Vidales 3, Adriana Longoria 4, José Luis Pinilla 1,* and Isabel Suelves 1Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe paper has certain novelty and originality, and the language standard and structure of the paper are reasonable. It is recommended to accept after modification.
1. The order of the headings in the paper is confused, please revise it carefully. For example,1. METHODOLOGY， 2.1. Materials ，2.1. Catalyst synthesis ，2.1. Hydrodeoxigenation of bio-oils，and so on.
2. XRD, the most critical characterization method for the synthesis of samples, is missing.
3. A more clear SEM image with magnification is required in Figure 1.
Author Response
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Reviewer 2 Report
Comments and Suggestions for AuthorsThis paper is an interesting study on the refining of real bio-oil feedstocks using molybdenum carbide based catalysts. This paper can be published after answering the following comments, questions and suggestions.
1 Page 1 Line 20. ...to obtain high rates of deoxygenation (69-72%). It is impossible to draw a conclusion about the rate from the value of the degree of deoxygenation. In this case, it is better not to use the term rate.
2 In the literature review on carbide catalysts, it is also possible to refer to some papers by this research group led by Professor Yakovlev https://doi.org/10.3390/catal13050870, https://doi.org/10.1007/s11244-019-01211- z and https://doi.org/10.3390/catal8110560.
3 When describing the literature on the use of alcohols as hydrogen donors in deoxygenation processes, one can refer to earlier works, such as https://doi.org/10.1021/acscatal.6b03201 , https://doi.org/10.1016/j.apcata.2022.118792 , https://doi.org/10.1002/cctc.201601590 and https://doi.org/10.3390/catal12111307
4 The description of the deoxygenation process 2.1 states that the hydrogen pressure was 10 bar at the beginning. However, the introduction discusses the use of ethanol as a hydrogen donor. Why should additional hydrogen gas be used?
5 Also, in paragraph 2.1, line 140, it is described that the temperature was 350°C, but later the temperature of the described experiments was chosen to be 200 and 250°C. Please clarify this fact.
6 When describing Figure 4, the temperatures of the processes should be given.
7 Different temperatures A200 and C250 were used for two types of bio-oil. What is the reason for conducting experiments at different temperatures? In the future, these two types of bio-oil are compared, but the conditions of transformation are too different. Perhaps experiments should be carried out at the same temperature. Or choose the same type of bio-oil and two different temperatures.
8 In the description of Table 3, it is unclear what the numbers mean. If it is a percentage molar composition, how was it determined by the GC-MS method? To determine the exact composition by this method, it is necessary to know the calibrations of these substances, since the sensitivity coefficients for these types of substances are very different.
9 When describing Table 4, the total residual pressure in the system after cooling should be reported for each experiment.
10 Item 4. You need to correct the name of the item. There should be a conclusion, not a Type of the PaperCONCLUSIONS.
Author Response
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Reviewer 3 Report
Comments and Suggestions for AuthorsThe authors presented an interesting piece of work on bio-upgrading. Other than some minor typos, the manuscript is reasonably well presented.
I suggest the author to further analyse the FTIR data on the evolution of intermediate species with respect to time. The reaction mechanism, even partially studied, will be a strong addition to the manuscript.
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Round 2
Reviewer 1 Report
Comments and Suggestions for Authors1. XRD, the most critical characterization method for the synthesis of samples, is missing，the authors need to provide test results..
Author Response
The reviewer is right. Diffractogram of the catalyst along with some discussion have been added to the revised version of the manuscript (please see the attachment).
Author Response File: Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsAll comments have been taken into account.
Author Response
Authors thank the reviewer very much for its comments, which helped to improve the discussion of the manuscript.
