Effect of Reaction Time on the Morphology and Visible-light Photocatalytic Property of Bismuth Tungstate

The bismuth tungstate(Bi2WO6) samples with micro-dish morphologies were synthesized by a simple hydrothermal method for different reaction time.The crystal structure,compositions,morphology,morphology,optical absorption property and photocatalytic activities of the samples were characterized.The results indicate that the hydrothermal time played a key role in the morphology of Bi2WO6.The sample was poorly crystallized after 6 h of the hydrothermal process.As the hydrothermal time increasing,the morphologies of Bi2WO6were transformed from a two-dimensional plate-like structure to a threedimensional dish-like structure.After 48 h of the hydrothermal reaction,a microstructured dish-like shape was completely formed.The Bi2WO6synthesized at 180 ℃ for 48 h had higher ·OH formation rate and better visible-light-driven photocatalytic activity.Neither longer nor shorter reacting time can improve the photocatalytic performance of Bi2WO6.Moreover,the formation mechanisms of Bi2WO6under different hydrothermal time were investigated.