Band alignment engineering for improved performance and stability of ZnFe2O4 modified CdS/ZnO nanostructured photoanode for PEC water splitting

ZnFe2O4 modified CdS quantum dots/ZnO nanorods core/shell structured photoanode has been designed and successfully fabricated. With the decoration of ZnFe2O4, both the photoelectrochemical performance and the stability of the CdS/ZnO photoanode were enhanced. The improved photoelectrochemical performance can be attributed to the typical stair-like type-II band alignment between ZnFe2O4, CdS and ZnO. The heterojunction between ZnFe2O4, CdS and ZnO can enhance the separation efficiency of the charge carriers. In addition, ZnFe2O4 nanoparticles can serve as holes receptor of CdS and act as a protective layer which will reduce the photocorrosion of CdS and improve the stability of the photoanode. The optimized photoanode exhibited a remarkable solar-to-hydrogen efficiency of 4.4% which was 15.7 times than that of the pristine ZnO photoanode. This work provides a strategy for designing and fabricating stable and efficient photoanode. (C) 2016 Elsevier Ltd. All rights reserved.