Microwave-assisted hydrothermal solution process for accelerated formation of 3D hierarchical flowery anatase-TiO2 microspheres with excellent photocatalytic activity

Abstract

A microwave-assisted hydrothermal solution synthesis methodology is used to prepare 3D hierarchical flowery TiO₂ microspheres quickly and without calcination. The X-ray diffraction analysis showed that the microspheres are crystallized in the anatase form. Scanning electron microscopy showed that the anatase 3D hierarchical flowery TiO₂ microspheres comprised many nm-thick petal-like features evenly distributed in each microsphere. The use of microwaves (for only 10 min at 200 W) acted as the additional source of energy that resulted in the accelerated growth of flowery TiO₂ microspheres that otherwise would require long durations to form under only hydrothermal conditions. The microspheres exhibited a large specific surface area of 87.58 m² g⁻¹ and unique pore characteristics, making them suitable for photocatalysis. In this context, the measured photodegradation efficiency of the 3D hierarchical flowery anatase-TiO₂ microspheres in degrading methylene blue dye was as high as 98%.