Stability of WO<sub>3</sub>/CuO Heterojunction Photoelectrodes in PEC System

Abstract

The tungsten trioxide (WO 3 ) and copper(II) oxide (CuO) photoelectrodes have been fabricated from acidic aqueous solution of peroxy-tungstate and basic aqueous solution of copper sulphate-lactic acid respectively, by electrodeposition method. The samples produced were calcined at 450 °C for 30 minutes before the deposition of second layer. The CuO was layered on WO 3 sample by electrodeposition of basic aqueous solution of copper sulphate-lactic acid, followed by annealing process at 450 °C for 30 minutes. On the other hand, the WO 3 layer was casted onto CuO sample by sol-gel method and it was annealed at 450 °C for 30 minutes. The resulting samples were then characterized by XRD to confirm their structures. Photoelectrochemical characterization of the WO 3 , CuO and WO 3 -CuO bilayer photoelectrodes were carried out under 100 W xenon light illumination, in 0.5 M sodium sulphate solution with saturated calomel electrode (SCE) reference electrode and platinum counter electrode. The PEC stability of the electrodes was evaluated at -0.7 V vs SCE under irradiated condition.