Titanium dioxide (TiO2) and copper oxides have been known for n-type and p-type semiconductor photocatalytic effects respectively. In this research, a solar cell was constructed with TiO2 and copper oxides as anode and cathode of the cell with seawater electrolyte. The polarization of TiO2 and copper oxides was measured. The cell current density and cell power density against cell voltage were measured and analysed. From those results, Electrochemical Impedance Spectroscopy (EIS) was performed. The Cole-Cole plot was obtained, and equivalent circuit was constructed. The results were compared with TiO2 vs Stainless steel cell results since stainless steel is base substrate of copper oxides electrode and its passive film shows photocatalytic semiconductor effect. The power density of TiO2 vs copper oxides cell was much higher than that of TiO2 vs Stainless steel cell. By EIS analysis, internal resistance of the cell was reduced by introducing copper oxides electrode to the cell.