Effect of reactant sequence on the structure and properties of self-assembled TiO2 microspheres with exposed {001} surfaces

Abstract

Highly exposed {001} surfaces of ITD-TiO₂ and IDT-TiO₂ microspheres with a self-assembled hierarchical structure were prepared via an intermittent two-step hydrothermal method. ITD-TiO₂ possesses a polycrystalline structure, and the particle size is about 500 nm. The specific surface area of ITD-TiO₂ was found to be 199.21 m² g⁻¹, which is significantly larger than that of P25. ITD-TiO₂ exhibited excellent photocatalytic activity; the degradation rate of MO reached 99.0% after UV-light irradiation for 3.0 h and is 63.6% higher than that of P25. The surface photovoltage of IDT-TiO₂ heat-treated at 500 °C was 264 μV, which indicates that more carriers can be generated inside the sample during the photocatalytic process. Moreover, the order of adding the titanium source and morphology control agent in this research system is the key factor affecting the morphology of the sample. This is mainly because the hydrolysis and nucleation of tetrabutyl titanate in the precursor solution is affected by diethylenetriamine.