Fabrication of three-dimensional CdS nanosheets/ZnO nanorods hierarchical heterostructure for improving photoelectrochemical performance

In this paper, a unique three-dimensional CdS nanosheets/ZnO nanorods hierarchical heterostructure film as photoelectrode was designed and synthesized to improve the photoelectrochemical performance. Through the UV-vis absorption spectra, it can be seen that the light absorption properties of CdS nanosheets/ZnO nanorods composite films has been significantly improved. This is attributed to its proper three-dimensional hierarchical structure, which greatly enhances the light scattering and multi-reflection effects. Meanwhile, according to the results of photoelectrochemical measurements, the high-quality heterostructure formed between ZnO nanorods and CdS nanosheets can effectively promote the transmission and separation of photo-generated charges, thus increasing the photocurrent density. Under the light irradiation of 100 mW cm−2, the optimal photocurrent density of three-dimensional CdS/ZnO-2.5 composite film at 0 V is 9 mA cm−2, which is about 3.6 times higher than that of pure ZnO nanorod array film. This work provides an effective strategy for obtaining high-performance ZnO-based photoelectrodes by designing appropriate three-dimensional heterostructures.