Production of hydrogen by water splitting in a photoelectrochemical cell using a BiVO4/TiO2 layered photoanode

Abstract BiVO 4 /TiO 2 layered photoanode was prepared by simple methods, such as sol-gel and metal organic decomposition processes. The photoanode was studied for hydrogen production by water splitting under simulated solar irradiation. Various multilayer configurations of the film were electrochemically tested. The optimal combined photocatalyst consisted of four bottom BiVO 4 layers covered by four TiO 2 layers on the top. This optimal layered film was characterized by XRD measurements, which showed the presence of the most photoactive phases of BiVO 4 and TiO 2 . The energy band gap measured by diffuse reflectance spectroscopy demonstrated a small blue shift compared to pure BiVO 4 . Solar-to-hydrogen efficiency reached 1.1% at 1.08 V vs. RHE. The corresponding faradaic efficiency was 64%. The photocurrent at 2.08 V vs. RHE for the optimal BiVO 4 /TiO 2 photoanode was approximately 5.5 mA/cm 2 . Hydrogen production rate was measured at different external bias from 1.08 to 2.08 V vs. RHE and the cumulative production reached 0.6 mmol after 10 hours of irradiation at 2.08 V, which was the highest reported for the BiVO 4 /TiO 2 system.