Improved Stability and Photoelectrochemical Performance of Al2O3 Passivated CdS/1D Zr:Fe2O3 Heterojunctions for Solar Hydrogen Generation

Abstract

Al2O3 passivated CdS sensitized 1D Zr:Fe2O3 nanorod arrays have been synthesized on fluorine-doped tin oxide (FTO) by hydrothermal method and dip coating methods. The photoelectrochemical study of CdS/1D Zr:Fe2O3 photoelectrode exhibits the current density of 4.2 mA.cm-2 at 0 V (vs. Ag/AgCl) which is 2.8 time higher than the bare 1D Zr:Fe2O3. The reduced recombination and the effective transport of photogenerated holes in CdS facilitates the enhancement in photoelectrochemical performance. Furthermore, the photocurrent and stability of the CdS/Zr:Fe2O3 nanorods was significantly enhanced by Al2O3 compared to bare CdS/Zr:Fe2O3 heterojunction due to its ability to act as an effective hole transport as well as photocorrosion protecting layer. The chemical analyses and nanostructural study of the Al2O3 coated CdS/1D Zr:Fe2O3 photoelectrodes confirms the presence of Al2O3 on surface of CdS and 1D Zr:Fe2O3 nanorods embedded in the CdS flakes. These remarkable enhancements in light energy harvesting, improvement in charge transport and stability directly suggest the usefulness of photoelectrodes for solar hydrogen generation. KEYWORDS: Al2O3 passivation; Zr:Fe2O3 nanorod arrays; CdS Sensitizer; Hydrogen generation ACKNOWLEDGMENT This research was supported by the BK21 plus program, the Korean National Research Foundation (Nano-Material Fundamental Technology Development, 2016M3A7B4909370).