r/science • u/Wagamaga • Aug 06 '20

Chemistry Turning carbon dioxide into liquid fuel. Scientists have discovered a new electrocatalyst that converts carbon dioxide (CO2) and water into ethanol with very high energy efficiency, high selectivity for the desired final product and low cost.

https://www.anl.gov/article/turning-carbon-dioxide-into-liquid-fuel
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u/hoyeto Aug 06 '20

but water electrolysis to produce hydrogen has 100% faradaic efficiency

Really? What is your source? Because electrolysis is very energy inefficient and requires expensive catalysts like silver. It is well known there is not enough silver in the world to make these devices scalable.

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u/DasSpatzenhirn Aug 06 '20

Faradaic efficiency is the electrochemical equivalent of selectivity. Which basically means that you create 100% hydrogen at the Kathode and nothing else. In co2 electrolysis you create many other byproducts such as CO, H2 and Formic acid

The energy efficiency of a hydrogen electrolysis is about 70%.