Fig. 4. CO₂RR performance at 84% CO₂ and operando XAS characterization.

a Methane FEs on different catalysts at 84% CO₂. b Comparison of methane FEs on different catalysts at 200 mA cm⁻². Error bars represent the standard deviation based on three separate measurements. c Comparison of ${\mathrm{FE}}_{{\mathrm{CH}}_4}/{\mathrm{FE}}_{{\mathrm{H}}_{2+}}$ ratios on different catalysts at 84% CO₂. d Operando Cu K-edge XANES spectra of different catalysts during CO₂RR with a constant current density of 200 mA cm⁻². Bulk Cu foil, Cu₂O, and CuO are listed as references.