Heterogeneous Electrocatalysis of Carbon Dioxide to Methane

Round 1

Reviewer 1 Report

The authors focused on the Electrocatalytic conversion of CO2 to CH4 using heterogeneous catalysts, especially on Cu-based catalysts. They discussed from the catalyst engineering and electrolyte effect. The fundamental mechanism of the reaction is also covered. In the end, the future outlook in the field is given as well. However, there're some issues in the paper.

1. The justification for CH4 generation is not enough and adequate in the introduction. The authors need to compare it with other potential reduction products in a bigger picture. Some aspects include the market share and market price. 

2. The references are not very new. Most of the cited papers published couple of years ago. I was wondering if the authors can highlight some most recent examples (2020-now). Here is a recommended review paper published this year for the authors attention (DOI: 10.1039/d2nr02894h). Besides this one, other papers need to added so that the readers can get the most up to date information in the field.  

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

This paper summarizes the recent advances in the electrocatalytic reduction of CO₂ to CH₄. The authors focused on reviewing the Cu-based catalysts. What about other catalysts?

I suggest that the authors summarize the different methods of converting CO₂ to CH₄, then explain the electroreduction process and its advantages compared to the other strategies.

Can the electroreduction of CO₂ to CH₄ be performed in other electrolytes other than the aqueous electrolytes? If yes, examples are needed to be included in the review.

The authors claimed that one of the advantages of converting CO₂ to CH₄ is to mitigated the greenhouse effect. CH₄ is also a greenhouse gases and it is even more powerful greenhouse than CO₂. More explanation is needed regarding this point.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The quality of this paper has been improved.