fig9

Figure 9. EIS and Equivalent Circuit of Ti/Fe2O3 photoanode, Ti/Fe2O3/Cu2S photoanode and Ti/Fe2O3/Cu2S/Co(OH)x photoanode at (A) 1.23 V vs. RHE and at (B) OCP. EIS: Electrochemical impedance spectroscopy; RHE: reversible hydrogen electrode; OCP: open circuit potential.