The visible-light photocatalytic activity of BiFeO3 can be enhanced by treating in LiNO3 molten salt. BiFeO3 is prepared by pyrolysis of tartaric acid complex. The as-prepared BiFeO3 is mixed with LiNO3 salt by ball milling for 4 h with the molar ratio 12∶1 of LiNO3 to BiFeO3. The mixture was heated at 270 ℃ for 12 h, and LiNO3 was removed from the product by washing with distilled water. The visible light photocatalytic activity is evaluated by measuring the decoloratation of Congo red aqueous solution. After heating in LiNO3 molten salt, the decoloratation of Congo red aqueous solutions increased significantly from 31.6% to 95.4%. The enhancement of the photocatalytic activity is attributed to surface modification of BiFeO3 by treating in LiNO3 molten Salt.
