Hierarchically ordered macro-mesoporous anatase TiO 2 prepared by pearl oyster shell and triblock copolymer dual templates for high photocatalytic activity.

Hierarchically ordered macro-mesoporous anatase TiO 2 is prepared by combining the supramolecular-templating self-assembly of amphiphilic triblock copolymer P123 with a natural pearl oyster shell in a hard-templating process by a facile sol-gel reaction. The obtained materials are characterized by Raman spectroscopy, X-ray diffraction, N 2 adsorption-desorption analysis, scanning electron microscopy, and transmission electron microscopy. The results demonstrate that all TiO 2 materials obtained after calcination at various temperatures are in the anatase phase, and interestingly the resultant ordered structure of both macropores and mesopores are well-preserved after calcination at 350 °C or 450 °C, with the walls of macropores composed of ordered mesopores. However, upon calcination at 550 °C or 650 °C, while the ordered macroporous structures remain well-preserved, the mesoporous structures collapse. The photocatalytic activities of the resulting TiO 2 materials are also evaluated by photodegradation of rhodamine B under UV light irradiation. The prepared TiO 2 calcined at 450 °C shows the highest photocatalytic activity.