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

Bilayer n-WO3/p-Cu2O photoelectrode films on fluorine-doped tin oxide (FTO) coated glass have been synthesized by consecutive electrodeposition of tungsten trioxide (n-WO3) and cuprous oxide (p-Cu2O) films from acidic aqueous solution of peroxytungstate and basic aqueous solution of copper sulfate-lactic acid by electrodeposition method. The WO3 film was annealed at 350 °C for 30 min to obtain a crystalline WO3 before the second layer of Cu2O was incorporated. Photoelectrochemical characterization of the WO3, Cu2O and WO3/Cu2O photoelectrodes were carried out under 100 W xenon light illumination, in 0.5 M Na2SO4 solution with saturated calomel electrode (SCE) as a reference and a platinum wire as the counter electrode. Investigation on the oxidative nature of the Cu2O on both mono and bilayer electrode films was carried out and a mechanism scheme was suggested. The photocurrent generated by n-WO3/p-Cu2O bilayer photoelectrode was much higher compared to the plain n-WO3 and p-Cu2O.