Fig. 3: Activation energy assessment and CO₂R using CO₂ streams with different partial pressures.

CO₂R current densities and FEs for all measurable products at different temperatures at applied potential of –1.0 V_RHE in 0.1 M KHCO₃ for Cu₅Ga₁ (a) and Cu (b). a, b No iR correction. The corresponding Arrhenius plots for C₂H₄ (c) and H₂ (d) productions during CO₂R. The ECSA for Cu and Cu₅Ga₁ in H-cell is 83.4 and 91.3 cm², respectively. CO₂R product distribution using different CO₂ partial pressure at current density of 0.5 A cm^–2 for Cu (e) and Cu₅Ga₁ (f), measured in flow cell using 1 M KOH as the electrolyte. gThe applied potential (left) and the ratio of FE_C2+ to FE_H2 (right) under different CO₂ partial pressure for CO₂R on Cu and Cu₅Ga₁ under different current density. 100% iR correction was applied to calculate the applied potential. The solution resistance (R): Cu-100, 3.23 ± 0.9 Ω; Cu-500, 2.61 ± 0.6 Ω; Cu₅Ga₁-500, 2.21 ± 0.8 Ω; Cu₅Ga₁-1000, 2.06 ± 0.4 Ω. Details about the recorded process can be found in the Method section. h The FE_C2+ for CO₂R on Cu and Cu₅Ga₁ catalysts at different current densities with different CO₂ partial pressure. The error bars in a–d were standard deviations which determined from at least 3 independent experiments. Relevant source data for this figure are provided in the Source Data file.