Electrocatalytic CO₂ Reduction Reaction: Formulas for Calculating Key Activity Rating Indices

Products of Electrochemical CO₂ Reduction

Through electrocatalysis, CO₂ can be converted into high-value chemicals such as CO, CH₄, HCOOH, C₂H₄, C₂H₅OH, etc^[1].

The variety of products in the CO₂ reduction reaction results from the different numbers of electrons required during the reaction. Therefore, the calculation methods for different product yields in the CO₂ reduction reaction are closely related to the transferred number of electrons during the reaction process.

A table has been compiled to clarify the specific products in the CO₂ reduction reaction and their corresponding transferred electron numbers, as shown in Table 1.

Table 1. CO₂ reduction to various products and corresponding electrode reactions^[2]

Key Activity Rating Indices for Electrochemical CO₂ Reduction

1. Faradaic Efficiency

Faradaic efficiency refers to the percentage of the charge consumed for the target product compared to the total charge consumed in the reaction, describing the selectivity of products in the electrocatalytic reaction^[3].

For the Faradaic efficiency of gaseous products, the calculation method is as follows^[4]:

For the Faradaic efficiency of liquid products, the calculation method is as follows^[5]:

 

2. Local Current Density

Local current density (j_product) refers to the current density required for the target product. The formula is as follows^[6]:

 

3. Cathodic Energy Efficiency

Cathodic Energy Efficiency (CEE) refers to the percentage of chemical energy contained in the reduced product compared to the total input electrical energy. The formula is as follows^[7]:

 

4. Turnover Frequency

Turnover Frequency (TOF), i.e., the number of conversions per active site per unit time, is calculated as follows^[8]:

 

The information above is sourced from literature, and the editor has compiled it. Corrections are welcome if there are any errors!

References