Morphology control of rutile TiO₂ with tunable bandgap by preformed β-FeOOH nanoparticles

Rutile TiO₂ are widely used for applications of coatings, cosmetics, photoelectric devices and so on. However, effective control of well-defined morphology, size and composition of rutile TiO₂ nanoparticles from agglomeration has always been a challenge. A new synthesis strategy was proposed to prepare rutile TiO₂ with controllable morphology varied from flower-like structures to single-separated nanorods. The β-FeOOH nanoparticles were generated by the hydrolysis of FeCl₃ solution and could prevent the aggregation of TiO₂ nanocrystals at early stages of the reaction; thus, could control the morphology of rutile nanoparticles. The morphology of rutile TiO₂ nanoparticles could be controllably regulated from flower-like structures to individually separated nanorods. Meanwhile, the preformed β-FeOOH also played a role of dopant. Fe ions were substitutionally doped into the bulk lattice of TiO₂ nanocrystals and reduced the bandgap, which extended the solar radiation absorption range of rutile TiO₂. The prepared TiO₂ may be suitable for novel UV-blue light shielding agents and many other applications in photoelectric devices, photocatalysis, and so on due to its small size, unprecedented discrete rod-like structure and unique UV-vis light permeability.