Facile Fabrication and High Photoelectric Properties of Hierarchically Ordered Porous TiO2

This paper presents the first successful fabrication of hierarchically ordered porous (HOP) TiO2. Poly(styrene-co-acrylic acid) colloidal spheres and triblock copolymer P123 were used as macro- and mesoporous structure-directing agents, and titanium chloride and titanium tetraisopropoxide were used as sources of titania. When the mixture of polymer spheres, P123, and titania precursors were cast on substrates, and conducted for complete solvent evaporation, followed by thermal treatment, large-scale HOP TiO2 can be directly fabricated. The in situ chelate effect between the titania precursors and the poly(styrene-co-acrylic acid) plays a key role in the fabrication of HOP TiO2. The as-obtained HOP TiO2 exhibits 50% and 70% greater the highest photocurrent under UV and visible lights, respectively, and far higher photoelectrocatalytic property than commercial TiO2 (P-25).