Preanodized Cu Surface for Selective CO₂ Electroreduction to C₁ or C₂₊ Products.

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrochemical CO2 reduction (CO2R) is promising for chemical synthesis.
• Controlling product distribution in CO2R over copper (Cu) catalysts remains challenging.

Purpose of the Study:

• To demonstrate effective regulation of CO2 reduction pathways using preanodization of Cu electrodes.
• To investigate the influence of electrolyte composition during preanodization on Cu surface structure and CO2R product selectivity.

Main Methods:

• Preanodization of Cu foil electrodes in NaClO4 and Na2HPO4 electrolytes.
• Electrochemical CO2 reduction experiments.
• In situ characterizations including electrochemical Raman, ATR-SEIRAS, and SEM.

Main Results:

• Preanodization in NaClO4 (Cu-NaClO4) yielded superior C1 product selectivity.
• Preanodization in Na2HPO4 (Cu-Na2HPO4) resulted in preferential C2+ product selectivity.
• Cu-NaClO4 featured Cu nanocrystals with dominant Cu(111) facets, favoring C1 products.
• Cu-Na2HPO4 formed unique Cu nanodendrites, enhancing CO intermediate adsorption and facilitating C-C coupling for C2+ products.

Conclusions:

• Surface structure engineering of Cu electrodes via preanodization is a viable strategy to control CO2 reduction product distribution.
• The findings provide insights into rational design of catalysts for selective CO2 conversion into valuable chemicals.