Gamma Ray Radiation Effect on Bi2WO6 Photocatalyst

The development of Bi2WO6-based materials has become one of research hotspots due to the increasing demands on high-efficient photocatalyst responding to visible light. In this work, the effect of high energy radiation (gamma-ray) on the structure and the photocatalytic activity of Bi2WO6 nanocrystals was first studied. No morphological change of Bi2WO6 nanocrystals was observed by SEM under gamma-ray radiation. However, the XRD spectra of the irradiated Bi2WO6 nanocrystals showed the characteristic 2 theta of (113) plane shifts slightly from 28.37 degrees to 28.45 degrees with the increase of the absorbed dose, confirming the change in the crystal structure of Bi2WO6. The XPS results proved the crystal structure change was originated from the generation of oxygen vacancy defects under high-dose radiation. The photocatalytic activity of Bi2WO6 on the decomposition of methylene blue (MB) in water under visible light increases gradually with the increase of absorbed dose. Moreover, the improved photocatalytic performance of the irradiated Bi2WO6 nanocrystals remained after three cycles of photocatalysis, indicating a good stability of the created oxygen vacancy defects. This work gives a new simple way to improve photocatalytic performance of Bi2WO6 through creating oxygen vacancy defects in the crystal structure by gamma-ray radiation.