High-efficiency photoelectrochemical electrodes based on ZnIn2S4 sensitized ZnO nanotube arrays

Well aligned ZnO nanorods (NRs) and nanotubes (NTs) based core/shell nanoarrays were fabricated by hydrothermal chemical conversion and directional chemical etching method and used as photo-electrochemical (PEC) electrodes. The experimental results reveal that the optimum structure is the ZnO/ZnS/ZnIn2S4 NT arrays, such a novel PEC electrode has attained a hydrogen generation efficiency of 8.86%. This better result is attributed to the enhanced absorption efficiency, appropriate gradient energy gap structure and fast electron transfer rate of one-dimensional (1D) NT, which implies a promising application in PEC water splitting. In this paper, we also focus our study on the correlation between the properties of PEC electrode and the nanoarrays structure (including nanorods and nanotubes, binary and ternary sensitizer, buffer layer), and the formation mechanism of NT based on chemical etching process. By adjusting the amount of reactants and reaction time, the core/shell nanostructure can be tuned from NR to NT and formed buffer layer. (C) 2014 Elsevier B.V. All rights reserved.