A hydrothermally grown CdS nanograin-sensitized 1D Zr:α-Fe₂O₃/FTO photoanode for efficient solar-light-driven photoelectrochemical performance

Well-defined CdS nanograin-sensitized one-dimensional (1D) Zr:α-Fe₂O₃ nanostructured arrays with enhanced photoelectrochemical performance are synthesized directly on F-doped SnO₂ (FTO) using the hydrothermal method. Owing predominantly to the appropriate photogenerated electron-hole separation and charge collection in 1D Zr:α-Fe₂O₃ nanorods, hydrothermally deposited CdS/1D Zr:α-Fe₂O₃ samples exhibit improved photocurrent density over CdS/Fe₂O₃ nanosheets prepared by other methods. In our work, compared with 1D Zr:α-Fe₂O₃, the CdS-sensitized 1D Zr:α-Fe₂O₃ nanorod arrays show 1.9 times improved photoelectrochemical performance. Unfortunately, CdS nanograin-sensitized 1D Zr:α-Fe₂O₃ nanorod arrays suffer from instability problem. Nickel hydroxide loading, however, can boost the photoelectrochemical performance of the heterojunction and also act as a protective layer that improves the stability of the Ni(OH)₂/CdS/1D Zr:α-Fe₂O₃ electrode compared to CdS/1D Zr:α-Fe₂O₃. This enhanced PEC activity may be ascribed to the strong heterojunctions between CdS nanograins and 1D Zr:α-Fe₂O₃ nanorod arrays as well as effective charge separation. This work will provide a new insight into the fabrication and protection of many new photosensitive electrode materials to engineer photoelectrochemical and photocatalytic devices in the near future.