Facile synthesis of porous Bi2WO6 nanosheets with high photocatalytic performance

Abstract

Compared with the well-known three-dimensional Bi₂WO₆ nanosheet-assembled nanostructures, the free-standing two-dimensional porous Bi₂WO₆ nanosheets have seldom been reported. The possible reason is that Bi₂WO₆ nanosheets with a high surface-to-volume ratio usually tend to self-assemble or aggregate to form microspheres to reduce their surface energy. To prevent their aggregation, in this study, a new and facile self-assembled route, which includes the in situ ion-exchange reaction of Na₂WO₄ solution with the Bi(NO₃)₃ solid powder and the following high-temperature calcination, has been successfully developed to prepare the free-standing porous Bi₂WO₆ nanosheets. The ion-exchange reaction between the Bi(NO₃)₃ solid and Na₂WO₄ solution can in situ produce amorphous Bi₂WO₆ nanosheets, while the high-temperature calcination (500 °C) causes the formation of homogeneously porous structures in individual nanosheets during their phase transformation from amorphous to crystalline. The resultant porous nanosheets are composed of one-layer Bi₂WO₆ nanoparticles with a size of 30–50 nm, and there is a strong coupling interface among these nanoparticles. Photocatalytic experimental results suggest that the resultant porous Pt/Bi₂WO₆ nanosheets show a high photocatalytic performance for the decomposition of phenol solution. Considering their facile preparation, the present synthetic route may provide new insights for the design and fabrication of other nanostructured materials with various potential applications.