Synthesis of Pure Brookite Nanorods in a Nonaqueous Growth Environment

oleh: Mahmoud Hezam, Saif M. H. Qaid, Idriss M. Bedja, Fahhad Alharbi, Mohammad Khaja Nazeeruddin, Abdullah Aldwayyan

Format: Article
Diterbitkan: MDPI AG 2019-10-01

Deskripsi

Brookite TiO<sub>2</sub> is the most difficult TiO<sub>2</sub> polymorph to synthesize. The available methods in the literature to produce brookite nanostructures mostly use water-based techniques for the preparation of water-soluble Ti complexes first, followed by a hydrothermal growth of the brookite nanostructures. Besides its multi-step nature, achieving a single brookite phase and optimizing the aqueous growth environment are all issues to be hardly controlled. In this work, pure brookite TiO<sub>2</sub> nanorods are synthesized using tetrabutyl titanate Ti(OBu)<sub>4</sub> and Sodium Fluoride (NaF) as precursor materials in a simple non-aqueous one-pot solvothermal process. Alcoholysis of only Ti(OBu)<sub>4</sub> in ethanol resulted in pure anatase nanoparticles, while the addition of NaF was essential to promote the growth of highly pure brookite nanorods. The phase purity is confirmed by X-Ray Diffraction, Raman Spectroscopy, and High-Resolution Transmission Electron Microscopy. The growth mechanism is explained according to the Ostwald&#8217;s step rule, where Na<sup>+</sup> ions are anticipated to have a potential role in driving the growth process towards the brookite phase.