(217dn) Template-Free Synthesis of TiO2 Microcages With Improved Photocatalytic Activity | AIChE

(217dn) Template-Free Synthesis of TiO2 Microcages With Improved Photocatalytic Activity


Jiang, Z. - Presenter, Tianjin University
Tian, Y., Tianjin University
Yang, D., Tianjin University

Hollow titanium dioxide (TiO2) materials have received considerable attention in the past few decades because of its unique properties and many promising applications in environmental and energy areas. To date, various strategies have been developed for the preparation of hollow TiO2 structures. However, most of the resultant hollow structures by these strategies are spherical.

Herein, we report a template-free and room-temperature synthesis of polyhedral TiO2 microcages  by using (NH4)2TiF6 and NaOH as the reactants and the self-assembling agarose gel as the matrix. The resultant microcages have the edge sizes of 1.40 ± 0.33 μm, and their shells are about 48 nm in thickness with mesopores about 3.8 nm in size. The intermediate, TiOF2 crystals, may act an important role during the formation of this kind of polyhedral TiO2 microcages. The mesopores may be formed through removing the agarose gel fibers embedded in the shell. TiO2 microcage is further analyzed by the selective area electron diffraction (SAED) and high resolution TEM (HRTEM). This result confirms that the shell of TiO2 microcages consists of anatase TiO2 nanoparticles. All the TiO2 microcage samples exhibit superior photocatalytic activity than Degussa P25 for the decoloration rate of methyl orange (MO) under artificial solar light irradiation. Moreover, the degradation rates of MO by different TiO2 microcage catalysts calcined at different temperatures (400, 500, 600 oC) are compared. It indicates that TiO2 microcage annealed at 600 oC displays the biggest degradation rate in all TiO2microcage samples, which can be attributed to the best crystallinity.

This study may provide a novel and facile approach for the template-free and green synthesis of hollow structure materials.