Visible-Light Photocatalytic Activity of N-Doped TiO2Nanotube Arrays on Acephate Degradation

Abstract

Highly ordered nitrogen-doped titanium dioxide (N-doped TiO2) nanotube arrays were prepared by anodic oxidation method and then annealed in a N2atmosphere to obtain N-doped TiO2nanotube arrays. The samples were characterized with scanning electron microscope (SEM), X-ray powder diffraction (XRD), X-ray photoelectron spectrum (XPS), and UV-visible spectrophotometry (UV-vis) spectrum. Degradation of the insecticide acephate under the visible light was used as a model to examine the visible-light photocatalytic activity of N-doped TiO2nanotube arrays. The results show that N type doping has no notable effects on the morphology and structure of TiO2nanotube arrays. After N type doping, the N replaces a small amount of O in TiO2, forming an N–Ti–O structure. This shifts the optical absorption edge and enhances absorption of the visible light. N-doped TiO2nanotube arrays subjected to annealing at 500°C in N2atmosphere show the strongest photocatalytic activity and reach a degradation rate of 84% within 2 h.