CdS/Zr:Fe2O3 Nanorod Arrays with Al2O3 Passivation Layer for Photoelectrochemical Solar Hydrogen Generation

Abstract CdS‐sensitized 1 D Zr:Fe 2 O 3 nanorod arrays were synthesized on fluorine‐doped tin oxide substrates by a two‐step hydrothermal method. The photoelectrochemical results demonstrate that the current density (4.2 mA cm −2 at 0 V vs. Ag/AgCl) recorded under illumination for the CdS/1 D Zr:Fe 2 O 3 photoanodes is 2.8 time higher than the bare 1 D Zr:Fe 2 O 3 . The extended absorbance spectrum, the reduced recombination, and the effective transport of photogenerated holes in CdS to the electrolyte facilitate enhancement in the photoelectrochemical performance. From X‐ray photoelectron spectroscopy and TEM observations of the bare and aluminum oxide‐treated CdS/1 D Zr:Fe 2 O 3 photoanodes, we could confirm that the 1 D Zr:Fe 2 O 3 nanorods were covered by the CdS layer and Al 2 O 3 layer present on surface of CdS. Furthermore, the photocurrent and stability of the CdS/1 D Zr:Fe 2 O 3 nanorods was significantly enhanced by Al 2 O 3 compared to bare CdS/1 D Zr:Fe 2 O 3 heterojunction owing to its ability to act as an effective holetransport‐ as well as photocorrosion‐protecting layer. These remarkable enhancements in light‐energy harvesting, improvement in charge transport, and stability directly suggest the usefulness of photoanodes for solar hydrogen generation.