Titanium oxide-based 1D nanofilaments, 2D sheets, and mesoporous particles: Synthesis, characterization, and ion intercalation

In this work, we report on the large-scale synthesis of TiO₂-based one-dimensional (1D) nanofilaments (NFs) using a facile, bottom-up, one-pot, solution-processing synthesis protocol. Our method entails mixing TiB₂ commercial powders with tetramethylammoniumhydroxide (TMAH) in plastic bottles at 80°C for a few days under ambient pressure. The resulting lepidocrocite titania-based 1D NFs, with ∼ 5×7 Ų cross-sections self-assemble in a plethora of nanostructures that depend on solvent used for washing. In ethanol, they form mesoporous particles that are free flowing, and nearly spherical, with an average diameter in the ≈13 μm range. In water, they self-assemble into pseudo-two-dimensional flakes comprised of nanobundles. The formation of the NFs occurs at the TiB₂/reaction reagent interface allowing for the formation of core-shell configurations. The intercalating TMA⁺ cations between the NFs can be readily exchanged with H₃O⁺, Li⁺, Na⁺, Mg²⁺, Mn²⁺, Fe²⁺, Co²⁺, Ni²⁺, or Zn²⁺ cations. With zeta-potential values of ≈ − 50 mV, the resulting materials form quite stable colloids in water.