N/Zr-codoped TiO 2 nanotube arrays: Fabrication, characterization, and enhanced photocatalytic activity

Abstract

We firstly report an electrochemical approach to fabricating N/Zr-codoped TiO 2 nanotube arrays for photocatalytic applications. In this approach, TiO 2 nanotube arrays were first prepared by anodic oxidation using titanium anode and platinum cathode. Then the formed TiO 2 nanotube arrays and Pt were used as cathode and anode, respectively for subsequent formation of N/Zr-codoped TiO 2 nanotube arrays through an electrochemical process in the presence of a solution of Zr(NO 3) 4 and NH 4Cl. The morphology and composition of the N/Zr-codoped nanotube arrays were characterized using field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV–vis diffusion reflection spectroscopy (UV–vis DRS). The photocatalytic activities of the N/Zr-codoped TiO 2 nanotube arrays were evaluated by the degradation of a model dye, rhodamine B. We show that the codoping with N and Zr elements significantly improves the photocatalytic efficiency of TiO 2 nanotube arrays under both UV and visible light irradiation. XPS analysis suggests that the N impurities are interstitially doped into the TiO 2 lattice, also enhancing the visible light sensitivity. Findings from this study suggest that through a simple codoping approach, TiO 2 nanotube arrays with enhanced photocatalytic activity can be fabricated, thereby opening a new pathway to construct nanostructured TiO 2-based composite materials for photocatalytic applications.