A facile Pechini method to synthesize novel Bi12SiO20-Bi2SiO5 heterostructure photocatalysts with enhanced visible light photocatalytic activity

Novel Bi12SiO20-Bi2SiO5 heterostructure photocatalysts were prepared by controlling the molar ratio of Bi/Si in the reactants via Pechini method. With the increasement of the molar ratio of Bi/Si, the samples tend to be well-crystallized Bi12SiO20 and the content of Bi2SiO5 decreases in composites. Experiments reveal that the heterojunction shows higher visible light photocatalytic activity than pure Bi12SiO20 and Bi2SiO5 due to an increase in light harvesting efficiency and an efficient electron-hole separation. And the heterostructure photocatalyst is stable in the photocatalytic reaction process. The influence of some trapping agents on the photodegradation of Rhodamine B was investigated, and h(+) and center dot O-2 (-) were verified to play more important roles than center dot OH-.