Facile synthesis of mesoporous TiO₂ architectures with tunable configurations and nanometer precision

Titanium dioxide (TiO₂) can be used in various applications such as catalysis, sensing, energy storage and conversion due to its semiconducting and crystalline properties. Ordered mesoporous TiO₂ materials with high porosity values may further enable improvements in mass diffusion and surface access. However, despite the syntheses of TiO₂-based bulks and polymorphs in the past, it remains challenging to control mesoscopic TiO₂ morphology and dimension, pore shape and size, crystallographic phase and orientation. Here we describe a facile and robust solution-processed methodology for the preparation of a series of mesoporous TiO₂ structures with highly tailored architectures at the atomic scale, nanoscale and mesoscale. The process relies on the preformation of flexible micelle hydrogels and the stepwise assembly, under specific conditions to synthesize diverse mesoporous TiO₂ configurations with tunable parameters, such as bouquet-like spheres, chapped spheres, monolayered nanosheets, sandwich, vertical films and so on. The synthetic conditions and procedures are provided in detail to ensure the reproducibility of the experiments. The preparation of micelle hydrogels takes ~21 h, and the subsequent synthesis time to obtain versatile mesoporous TiO₂ is usually ~50 h. Our protocol is suitable for researchers in nanomaterials, porous and inorganic materials and other related disciplines.