fig6

Figure 6. Nyquist plots of Cu₂O (100) and HY-Cu₂O (100) collected at different potentials (A-F): EIS spectra recorded at open-circuit potential (OCP; Z ranges of 0-50 kΩ and 0-10 kΩ, respectively) (A and D); EIS spectra at 0.55 V vs. reversible hydrogen electrode (RHE); Z ranges of 0-50 kΩ and 0-10 kΩ, respectively (B and E); EIS spectrum at 0.35 V vs. RHE (Z range of 0-0.1 kΩ) (C); EIS spectrum at 0.15 V vs. RHE (Z range of 0-0.1 kΩ) (F). Electrochemical performance of Cu₂O (100) and HY-Cu₂O (100) measured in 0.1 mol L^-1 Na₂SO₄ electrolyte: Cyclic voltammetry curves of Cu₂O (100) under Ar atmosphere (G); Cyclic voltammetry curves of HY-Cu₂O (100) under Ar atmosphere (H); Double-layer capacitance values of Cu₂O (100) and HY-Cu₂O (100) (I). EIS: Electrochemical impedance spectroscopy; CV: cyclic voltammetry; CPE: constant phase element; W: Warburg element; R_s: solution resistance; R_ct: charge transfer resistance.