Preparation and photocatalytic properties of nanocrystalline ZnWO4/TiO2

In order to combine ZnWO4 and TiO2 to form a heterojunction, a sol-gel method combined with a hydrothermal method was used to synthesize a ZnWO4/TiO2 heterojunction to degrade methylene blue (MB). The phase composition, microstructure, and photocatalytic performance of the synthesized catalysts are researched. The experimental results show that the sample with the TiO2:ZnWO4 ratio of 1:2 exhibited rod-shaped morphology with a size of about 100 nm, and the heterojunction structure is formed at the interface of zinc tungstate and titanium dioxide. The sample with the TiO2:ZnWO4 ratio of 1:3 is composed of zinc tungstate, titanium dioxide with poor crystallinity and ZnTiO3 impurities, presenting a rod-like structure formed by agglomeration of particles. Compared with pure zinc tungstate and titanium dioxide, the nanocrystalline TiO2:ZnWO4 has a higher photodegradation rate. The sample with the TiO2:ZnWO4 ratio of 1:2 has the best photocatalytic performance, and the photodegradation rate of MB reaches 94.6%. The sample with the TiO2:ZnWO4 ratio of 1:3 has better adsorption characteristics, but the photodegradation rate decreases.

Automated summary

The ZnWO4/TiO2 heterojunction catalyst synthesized by sol-gel and hydrothermal methods shows excellent photocatalytic degradation ability. The sample with a TiO2:ZnWO4 ratio of 1:2 exhibits the best performance with a photodegradation rate of 94.6%, while the sample with a ratio of 1:3 has better adsorption characteristics but lower photodegradation rate.