Controllable synthesis and catalytic activity of bismuth silicate: Thin-layered photocatalysts with the effect of template agent

The heterogeneous bismuth silicate is a promising and environmental photocatalytic material. However, the cross-linked structure limits its catalytic activity. Here, we report a visible-driven composite photocatalyst with high catalytic activity, namely BOS-PS (layered Bi2O2SiO3-Si2Bi24O40 modified with template PS spheres), which can solve the problem. By controlling the concentration of template and changing the reaction time, the microscopic morphology can be adjusted to obtain effective heterojunction and heterogeneous interfaces as well as highly active exposed surfaces. In addition, compared with BOS (Bi2O2SiO3-Si2Bi24O40)-0PS (polystyrene microspheres), BOS-12PS has a thinner sheet structure, and the photocatalytic performance of BOS-12PS photocatalyst (98% within 90 min) is twice than that of BOS-0PS. The improved performance is mainly attributed to the increase of center dot OH radicals and the modulation of its energy band structure by the oxygen defect level. Specifically, on the one hand, BOS-12PS has more center dot OH radicals and can produce center dot O-2(-) on the surface. On the other hand, due to its upward-moving structure (Vo level), BOS-12PS plays an important role in the degradation of pollutants. Especially, the effective heterojunction formed by Bi2O2SiO3 and Si2Bi24O40 significantly improves the separation efficiency and redox capability of the sample.