BiOI/TiO2 nanotube arrays, a unique flake-tube structured p-n junction with remarkable visible-light photoelectrocatalytic performance and stability.
A series of unique flake-tube structured p-n heterojunctions of BiOI/TiO2 nanotube arrays (TNTAs) were successfully prepared by loading large amounts of BiOI nanoflakes onto both the outer and inner walls of well-separated TiO2 nanotubes using anodization followed by the sequential chemical bath deposition (S-CBD) method. The as-prepared BiOI/TNTAs samples were characterized by X-ray diffraction, electron microscopy, X-ray photoelectron spectroscopy, UV-vis diffuse reflectance spectroscopy and nitrogen sorption. The photoelectrocatalytic (PEC) activity and stability of the BiOI/TNTAs samples toward degradation of methyl orange (MO) solutions under visible-light irradiation (λ > 420 nm) were evaluated. The visible-light PEC performance of BiOI/TNTAs samples was further confirmed by the transient photocurrent response test. The results from the current study revealed that the 5-BiOI/TNTAs sample exhibited the best PEC activity, favourable stability, and the highest photocurrent density among all the BiOI/TNTAs heterostructured samples. The combined effects of several factors may contribute to the remarkable visible-light PEC performance for the 5-BiOI/TNTAs sample including a 3D connected intertube spacing system and an open tube-mouth structure, strong visible-light absorption by BiOI, the formation of a p-n junction, larger specific surface area, and the impact of the applied external electrostatic field.
School of Materials Science and Engineering, Hefei University of Technology, 193 Tunxi Road, Hefei 230009, P. R. China. ycwu@hfut.edu.cn.
Jiaqin
J
Liu
Lili
L
Ruan
Samuel B
SB
Adeloju
Yucheng
Y
Wu