Bilayer n-WO3/p-Cu2O photoelectrode with photocurrent enhancement in aqueous electrolyte photoelectrochemical reaction

Abstract Bilayer n -WO 3 / p -Cu 2 O photoelectrode films on fluorine-doped tin oxide (FTO) coated glass have been synthesized by consecutive electrodeposition of tungsten trioxide ( n -WO 3 ) and cuprous oxide ( p -Cu 2 O) films from acidic aqueous solution of peroxytungstate and basic aqueous solution of copper sulfate-lactic acid by electrodeposition method. The WO 3 film was annealed at 350 °C for 30 min to obtain a crystalline WO 3 before the second layer of Cu 2 O was incorporated. Photoelectrochemical characterization of the WO 3 , Cu 2 O and WO 3 /Cu 2 O photoelectrodes were carried out under 100 W xenon light illumination, in 0.5 M Na 2 SO 4 solution with saturated calomel electrode (SCE) as a reference and a platinum wire as the counter electrode. Investigation on the oxidative nature of the Cu 2 O on both mono and bilayer electrode films was carried out and a mechanism scheme was suggested. The photocurrent generated by n -WO 3 / p -Cu 2 O bilayer photoelectrode was much higher compared to the plain n -WO 3 and p -Cu 2 O.