In2O3:Sn/TiO2/CdS heterojunction nanowire array photoanode in photoelectrochemical cells

Abstract

The design of photoanode with highly efficient light harvesting and charge collection properties is important in photoelectrochemical (PEC) cell performance for hydrogen production. Here, we report the hierarchical In2O3:Sn/TiO2/CdS heterojunction nanowire array photoanode (ITO/TiO2/CdS-nanowire array photoanode) as it provides a short travel distance for charge carrier and long light absorption pathway by scattering effect. In addition, optical properties and device performance of the ITO/TiO2/CdS-nanowire array photoanode were compared with the TiO2 nanoparticle/CdS photoanode. The photocatalytic properties for water splitting were measured in the presence of sacrificial agent such as SO32− and S2− ions. Under illumination (AM 1.5G, 100 mW/cm2), ITO/TiO2/CdS-nanowire array photoanode exhibits a photocurrent density of 8.36 mA/cm2 at 0 V versus Ag/AgCl, which is four times higher than the TiO2 nanoparticle/CdS photoanode. The maximum applied bias photon-to-current efficiency for the ITO/TiO2/CdS-nanowire array and the TiO2 nanoparticle/CdS photoanode were 3.33% and 2.09%, respectively. The improved light harvesting and the charge collection properties due to the increased light absorption pathway and reduced electron travel distance by ITO nanowire lead to enhancement of PEC performance.