Catalytic Evaluation of Nanoflower Structured Manganese Oxide Electrocatalyst for Oxygen Reduction in Alkaline Media

Round 1

Reviewer 1 Report

Comments for Authors:

This paper presented “Catalytic Evaluation of Nanoflower Structured Manganese Oxide Electrocatalyst for Oxygen Reduction in Alkaline Media”. This is a  paper with properly discussing the results and technically up to date. Therefore, the manuscript can be published after some major changes.

The manuscript can be published after some major changes:

1) The authors should check carefully in whole manuscript subscripts and superscripts in chemical formulas, e.g., lines: 27, 28, 30, 217, 2018, 219.

2) In section 1. Introduction Authors should extend and discuss the recent progress of effective and low-cost materials for ORR, which can be used in Zn-air battery (Materials 13.9 (2020): 2115).

3) Authors used two times the same name „Discussion” in section 2 and 3. The name of section „3. Discussion”, should be remove, and text on page 7, lines 197-214, should be included in section „2. Results and Discussion”.

4) Shape of linear sweep voltammetry curves are incorrect (Figure 4). Authors should repeat this experiment.

5) Authors suggest that „nanostructure electrocatalysts improve electronic and catalytic properties because of the high surface area”, however the surface area is not very high. Authors should explain correcponds and explain catalytic properties.

6) Page 5, line 160, „the polarization curves for the ORR on rotating disk electrode as shown in Figure 7” the sentence is incorrect, because Figure 7 shows OER curves.

7) In section 2.5., authors should add charge and discharge polarization curves, galvanostatic discharge-charge cycling curves and compare these Results with pristine commercial Pt/C catalyst. Also authors should explain in more details advantages of use the proposed materials compare to pristine Pt/C catalyst.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

In this article, author reported nanoflower-like MnO2 catalyst structure and characterized by SEM, BET and other characterization method. Author demonstrated that number of electrons transferred for carbon VXC 72 mixed with nanoflower MnO2, carbon VXC-72 mixed with nanoflower mixed with nanowires and carbon VXC-72 mixed with nanowires are 3.68, 3.31 and 3.00, respectively which is very close to 4 e transfer model. The article is well written and suitable for publications. I have two following queries and author should give some information.

• Please include a Table with the ORR and OER properties of Mn-based catalyst.
• Please provide the PXRD analysis of MnO2 catalyst in different form

Thank you

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

I accept manuscript for publication in actual version after revision.