The photoelectrochemical measurements were conducted using a SP-300 BioLogic potentiostat and a typical 3-electrode system consisting of a Pt wire counter electrode, a Ag/AgCl (3.5 M KCl, 0.207 V vs. SHE) reference electrode and tested photoanodes as working electrodes with geometric irradiation area of 0.5 cm 2 . Photoanodes were irradiated by visible light (λ > 420 nm) using a 150 W Xe lamp (L.O.T.-Oriel) with light power density of ~ 150 mW cm -2 , equipped with a KG-3 (LOT-Quantum Design) heat-absorbing filter and a 420 nm longpass optical filter.