Titanium Dioxide Microscale and Macroscale Structures: A Mini-Review.

Titanium dioxide nanoparticles (TiO NPs) have some limitations, such as their low surface area, high bandgap energy, and low recycling ability. To overcome these limitations, TiO can be prepared in microscale/macroscale structures. TiO microscale structures, in comparison with TiO nanopowder, have higher surface areas, more tunable pore structures, and better top photocatalytic activity. In contrast, for TiO macroscale structures, although the surface area is lower than TiO nanopowder in many cases, they still achieve similar or better photocatalytic performance due to their unique properties. Moreover, both TiO microscale and macroscale structures can be easily recovered from reaction media. The difference between these two types of TiO structures is a function not only of size but also of the preparation process. Every type of TiO structure has its own advantages and disadvantages, as will be discussed further in the following pages. Future perspectives on this research field also will be discussed.