I am working on a project whose first part aims to reduce CO2 in water to syngas with a preferred v/v composition of 40% CO, 40% H2, 10% CO2, and 2% O2 (to be used later in fermentation).
I know that the half-equations involved are as follows.
On anode: 2H2O + 4e- = O2 + 4H+
on cathode: two competing reactions
2H+ + 2e- = H2
CO2 + 2H+ + 2e- = CO + H2O
I am still in the experiment design phase and I am trying to figure out which parameters and electrode configuration to test as starting point. Literature has many suggestions (e.g., as attached). One way I am trying to know which configuration results in my desired syngas composition is to see the faradaic efficiency obtained in those reports for reducing CO2 to CO. For that, I need to know how to (at least roughly) convert my desired CO fraction (40% v/v) to faradaic efficiency of CO production, so that I know which reported electrode configuration fits my need the most.
Note: I know this question might sound a little dumb (maybe I just need the reports with faradaic efficiency of 40%). But I just want to be sure that I have a solid starting point for my experiments.
Reference:
Jones, J. P., Prakash, G. S., & Olah, G. A. (2014). Electrochemical CO2 reduction: recent advances and current trends. Israel Journal of Chemistry, 54(10), 1451-1466.