Effective visible light-active boron and europium co-doped BiVO4 synthesized by sol-gel method for photodegradion of methyl orange

The figure shows a possible mechanism for the synergistic effects of boron and europium co-doping on the photocatalytic activity of BiVO4. Under visible light irradiation, on the one hand, the B 1s energy level situated above the valence band and it will form a narrower band gap than that of pure BiVO4. The electrons were excited from the B impurity level to the conduction bands, the O2 adsorbed on the surface captured the electrons to form O2−, which will react with the organic materials. On the other hand, Eu ions act as shallow electron-trapping centers. So, B and Eu species in the co-doped BiVO4 may improve the separation efficiency of photogenerated electrons and holes, which is the main reason for higher photocatalytic acitivity.