Preparation and photoelectrocatalytic activity of ZnO nanorods embedded in highly ordered TiO2 nanotube arrays electrode for azo dye degradation

In this article, the ZnO nanorods embedded in highly ordered TiO2 nanotube arrays (ZnO/TiO2 NR/Ts) electrodes were fabricated through two steps: (1) electrosynthesis of TiO2 nanotube arrays (TiO2 NTs) in HF solution by anodization method; (2) followed by cathodic electrodeposition of ZnO embedded in the TiO2 nanotube arrays. The morphological characteristics and structures of ZnO/TiO2 NR/Ts electrodes were examined by field-emission scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDX) spectroscopy, X-ray diffraction (XRD) analysis, and UV-vis spectra. The linear-sweep photovoltammetry response on the ZnO/TiO2 NR/Ts electrode was presented and the photocurrent was dramatically enhanced on the ZnO/TiO2 NR/Ts electrode, comparing with that on bare TiO2 NTs electrode. The photocatalytic and photoelectrocatalytic activity of ZnO/TiO2 NR/Ts electrode was evaluated in degradation of methyl orange (MO) in aqueous solution.