Synthesis and characterization of hierarchical TiO2 microspheres composed of nanorods: effect of reaction conditions on nanorod density

Abstract

Urchin-like hierarchical TiO₂ microspheres consisting of numerous nanorods were successfully synthesized by a facile hydrothermal process. The effects of reaction conditions (such as additives and reactant concentrations) on TiO₂ morphology, particularly on rod density, were systematically investigated. The relationship between rod density and rod diameter was discussed. Based on the above results including a morphological evolution study, a possible mechanism was also proposed to elucidate the growth process of hierarchical TiO₂ microspheres using nanorods as building units.