Fig. 6. Effect of halogenation time on the performance of the catalysts for CO₂ reduction reaction.

FEs of the products from electrochemical CO₂RR are shown versus the amount of time the Cu foils were subjected to anodic halogenation in KCl (a), KBr (b), and KI (c). d–f FEs of H₂, C₁, C₂, and C₃ products from the same results shown in the corresponding upper plot. Data were acquired during 40 min of electrochemical CO₂RR at a constant potential of ~ −1.11 V vs. RHE in 0.1 M KHCO₃ saturated with CO₂. Data legends apply to all plots in the same row. Source data are provided as a Source data file.