Preparation And Photocatalytic Properties Of WO₃-based Semiconductor Nanomaterials

As one of the ways of conversion and utilization of solar energy,compared with traditional heating reaction,photocatalysis has the advantages of clean,environmental protection,safety and easy control,etc.,and the preparation of photocatalyst with high catalytic activity has become a hot spot of current research.In this paper,WO₃ nanorods were prepared by high temperature hydrothermal method.On this basis,Cu₂O-WO₃and WO₃-Ti O₂ nanocomposites with different mole ratios were prepared by coprecipitation method and high temperature hydrothermal method respectively,and the photocatalytic properties of WO₃ composite semiconductor were studied.Cu₂O-WO₃ is composed of cubes and irregular particles.The UV-visible light test shows that compared with the 2.8 e V bandgap for pure WO₃ material,the absorption boundary of Cu₂O-WO₃ composite semiconductor with a molar ratio of 1:2 is redshifted to 540 nm,and the bandgap is reduced to 2.3 e V,extending the light response range to the visible region effectively.The photocurrent density of Cu₂O-WO₃ composite semiconductor at-0.6 V is up to-0.81 m A/cm²,10.7 times higher than that of WO₃under dark light.In the test of photodegradation of Rh B solution,the reaction rate constant of Cu₂O-WO₃ is 6.6 times higher than that of pure WO₃,showing excellent photodegradation performance.This indicates that the pn heterostructure formed by WO₃ and Cu₂O effectively promotes the separation of photogenerated carriers,improves their survival time,and significantly improves photocatalytic activity.The SEM characterization of WO₃-Ti O₂ composite semiconductor shows that Ti O₂ particles are loaded on the surface of WO₃ nanorods.The UV-visible spectrum test indicates that the absorption boundary of Ti O₂ is around 380 nm,and the absorption boundary of WO₃-Ti O₂ with 10mol%molar percentage of W/（Ti+W）expands to about420 nm,and the bandgap is about 2.95 e V,the utilization of visible light is enhanced and the absorption intensity is greatly proved.The photocurrent density of WO₃-Ti O₂ at a bias of 0.8 V is up to 1.55 m A/cm²,which is 7.37 times higher than that of Ti O₂ under dark light.In the test of degradation of Rh B solution,the photodegradation rate of WO₃-Ti O₂ reaches 87.8%,and the reaction rate constant is 3.83 times higher than that of pure Ti O₂,and the photodegradation performance is significantly better than other materials.WO₃-Ti O₂ composite semiconductor promotes the migration of photogenerated electron-hole pairs and improves its photocatalytic performance by virtue of energy band differences.