Impact of the Cathode Layer Printing Process on the Performance of MEA Integrating PGM Free Catalyst

Round 1

Reviewer 1 Report

The paper is poorly written and it is full of spelling and grammar errors. It seems that the authors didn't proofread their work at all! Ambiguous referencing like "FCH2 JU 2017 AWP and Budget_FINAL-20122016-Clean (ID 2892681" occurred several times in the text. There is also one instance of "Error! Reference source not found.," in the text that should be addressed. Table 1 itself contains so many spelling problems. The structures of most of the sentences are very difficult to understand for instance "The commercialized by the company Pajarito Powders as PGM free catalyst (Serov et al., 2012). I, therefore, reject this publication and ask the authors to provide the paper with one native English speaker to enhance its coherence and flow.

Author Response

Dear Reviewer, 

The manuscript has been revised and most of the sentences have been modified or rewritten. The references have been updated.

 

Reviewer 2 Report

Manuscript: catalysts-1211410

 

Title of manuscript: Impact of the cathode layer printing process on the performance of MEA integrating PGM free catalyst.

 

Authors: Pierre TOUDRET, Jean-François BLACHOT, Marie HEITZMANN and Pierre-André JACQUES

 

Comments:

 

In this paper, the authors propose platinum group metal free-based cathode active layers prepared using different printing techniques. The paper shows several points of interest. I would recommend acceptance of this paper, provided authors address the following points:

• Have the Authors verified if the surfaces/cross sections of the cathodes change (morphology/properties) with time?
• Fig.3. Please, insert comments and experimental conditions in the caption of Fig.3. The reference to Fig.3 in text should be corrected.
• More details concerning reproducibility in preparation/properties of the cathodes should be inserted.
• Several typos.

Author Response

Dear Reviewer, 

Thank you for your interesting comments on our document. 

The technique used to made the images of the cross section of the MEA has been used for decades to study the structure of the MEA by microscopy. We have never seen any evolution of the structure of the MEA by using this technique. The SEM images have been recorded just one day after having prepared the samples. 

The references in the text have been corrected and the legend of the figure modified to be more explicit.  

We added more detailed explanation of concerning the repeatability of our experiments in the experimental section of the document. 

Typos have been corrected. 

Reviewer 3 Report

The author investigated the influence of the CL structure on the performance of PGM-free catalyst.  Also, they studied the effect of MEF fabrication method on the cathode performance. Overall, the research idea is very interesting and novel; however, I have few points for author consideration.  

• The abstract should state which coating technique gives the best performance.
• SEM is an abbreviation for Scanning electron microscopy not Scanning electrochemical microscopy, so fix it, please.
• CL and GDL are mentioned first as abbreviations and defined later which is supposed to be the opposite.
• The first sentence of section 2.1 is not complete and understandable, please fix it.
• In section 3, it is mentioned that “only 1 curve is reported for each preparation technique but each experiment has been proceed twice”, so my question is the results or curves are close to each other’s or in other words, are the results consistent?
• Subfigures should be defined for the graphs in fig 2.
• What do you think the reason for the sharp decline in i at the value of around 0,07 (A/cm2) for CCB bar coating and CCB spray coating? Explain, please.
• I think the figures and data need to be processed more professionally.

Author Response

Dear reviewer, 

Thank you for your comments and remarks. We addressed them in the revised version of the document.

 The abstract has been modified. the following sentence has been added : "The coated membrane (CCM) made using the decal transfer process gives the best performances."

The abbreviation of SEM (scanning electron microscopy) has been modified accordingly. 

CL and GDL have been defined first and their abbreviations used later. 

The first sentence of the section 2.1 has been modified : "The 3D mesoporous structured PGM-free catalyst (PMF-011904) from Pajarito Powders company was integrated in the cathode catalyst layers of  the MEAs by different ways. This catalyst is based on a FeNx/C moiety integrated in a carbon matrix."

The results are consistent. The discrepancy between the electrochemical characterisation performed on the 2 sets of experiment is noted in the table 2.  For the polarisation curves, in order to have readable graphic, only 1 set of tests has been reported. We add to your attention a new graph with the polarisation curves for the 2 sets of tests in a separate document.  

The subfigures in figure 2 have been defined. 

The sharp decline of the polarisation curves for CCB technology in condition 3 is assigned to a flooding of the CL. The section 4 has been modified to give more clear explanations on that phenomenon. 

The figures have been revised.   

 

 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors extensively edited the paper and it is acceptable now.