Hydrothermal Synthesis of Iodine-Doped Nanoplates with Enhanced Visible and Ultraviolet-Induced Photocatalytic Activities

Jiang Zhang,Feiyu Kang,Yong Xu,Zheng-Hong Huang

doi:10.1155/2012/915386

Abstract

The iodine-doped Bi2WO6(I-BWO) photocatalyst was prepared via a hydrothermal method using potassium iodide as the source of iodine. The samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM) and selected area electron diffraction (SAED), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (DRS), and photoluminescence (PL) spectroscopy. The photocatalytic activity of I-BWO for the degradation of rhodamine B (RhB) was higher than that of pure BWO and I2-BWO regardless of visible light (>420 nm) or ultraviolet light (<400 nm) irradiation. The results of DRS analysis showed that the I-BWO and I2-BWO catalysts had narrower band gaps. XPS analysis proved that the multivalent iodine species including I0and were coadsorbed on the defect surface of Bi2WO6in I-BWO. The enhanced PL intensity revealed that a large number of defects of oxygen vacancies were formed by the doping of iodine. The enhanced photocatalytic activity of I-BWO for degradation of RhB was caused by the synergetic effect of a small crystalline size, a narrow band gap, and plenty of oxygen vacancies.

Highlights

To decompose the organic pollutants existing in water and air, the advanced oxidation technique of photocatalysis was applied to deal with the serious environmental problems
New crystal orientations or changes in preferential orientations are not observed in IBWO and I2-BWO comparing with pure BWO
The diffraction peaks of iodine-doped Bi2WO6 (I-BWO) and I2-BWO are obviously weaker and broader, which indicate smaller crystalline sizes comparing with pure BWO

Summary

Introduction

To decompose the organic pollutants existing in water and air, the advanced oxidation technique of photocatalysis was applied to deal with the serious environmental problems. The nitrogen-doped titanium dioxide was regarded as an effective case to improve the visible light photoresponsivity and to shift the optical absorption edge of TiO2 towards a lower energy, thereby increasing the photoactivity Among these nonmetal dopants, iodinedoping was paid more attentions owing to altering the surface charge, shifting the photoresponse from UV to visible region and acting as a conduction-band electron scavenger capable of inhibiting the rapid recombination of photoinduced electron-hole pairs [5,6,7,8,9,10,11,12,13,14,15,16,17]

Results

Discussion

Conclusion