Facile preparation of spherical TiO2 inverse opals with enhanced visible-light photodegradation of methylene blue.

In this work, the spherical TiO₂ inverse opal photonic crystals (IOPCs) have been successfully prepared through the combination of sol–gel and liquid phase deposition (LPD) method using SiO₂ spheres as the templates. The characterization results show that the spherical TiO₂ inverse opal structure can significantly increase the specific surface area and total pore volume. The photocatalytic experiments reveal that the removal rate of Methylene blue (MB) by TiO₂ with spherical inverse opal (IO) structure (TiO₂-710) was 98% under illumination for 40 min, while the degradation rate of TiO₂ without IO structure (TiO₂-Sol) was only 17.7%. Moreover, the TiO₂-710 sample exhibits the highest reaction rate constant, which is about 9.1 times that of TiO₂-Sol. The enhancement of photocatalytic activity can be attributed to the existence of the unique spherical inverse opal structure. [ABSTRACT FROM AUTHOR]