Fig. 4: Electrochemical CO₂R performance on Cu_0.9Zn_0.1 catalysts fabricated by co-sputtering and wet-chemical-etching at pH 1–13.5.

a C₂₊ FEs at different current densities at pH 1, 4, 7, and 13.5, respectively. b Single-pass C₂₊ yield at different CO₂ flow rates and current densities at pH 1, 4, 7, and 13.5 in a 13.5 cm² cell. c CO₂R stability curves with C₂₊ FEs at pH 4, 7, and 13.5 in a three-electrode flow cell. Current densities were optimized: 400 mA cm⁻² at pH 4, 300 mA cm⁻² at pH 7, and 150 mA cm⁻² at pH 13.5, respectively (spheres: C₂₊ FEs, lines: cathodic potentials). d C₂₊/C₁ ratios at different current densities at pH 1, 4, 7, and 13.5. e Comparison of C₂₊ FE, single-pass C₂₊ yield, and full-cell C₂₊ EE with previous reports (solid sphere: C₂₊ in electrocatalysis, hollow sphere: C_2–4 in thermocatalysis, Supplementary Tables 20, 21). f C₂₊ energy efficiency (EE) at different current densities at pH 1, 4, 7, and 13.5 (sphere: cathodic C₂₊ EE, square: full-cell C₂₊ EE). g CO₂R stability with C₂₊ and ethylene FEs at 150 mA cm⁻² for Cu_0.9Zn_0.1 coated with graphite/carbon nanoparticles using a slim two-electrode flow-cell (The changed current density cycles consist of the work period at −150 mA cm⁻² for 120 s (lower black line) and the regeneration period at −1 mA cm⁻² for 30 s (upper black line)). Error bars in a, b, d, f represent the standard deviation based on three independent measurements.