Issue 2, 2023

Polymorphic control in titanium dioxide particles


The hydrolysis–condensation reaction of TiO2 was adapted to the phase inversion temperature (PIT)-nano-emulsion method as a low energy approach to gain control over the size and phase purity of the resulting metal oxide particles. Three different PIT-nano-emulsion syntheses were designed, each one intended to isolate high purity rutile, anatase, and brookite phase particles. Three different emulsion systems were prepared, with a pH of either strongly acidic (H2O : HNO3, pH ∼0.5), moderately acidic (H2O : isopropanol, pH ∼4.5), or alkaline (H2O : NaOH, pH ∼12). PIT-nano-emulsion syntheses of the amorphous TiO2 particles were conducted under these conditions, resulting in average particle diameter distributions of ∼140 d nm (strongly acidic), ∼60 d nm (moderately acidic), and ∼460 d nm (alkaline). Different thermal treatments were performed on the amorphous particles obtained from the PIT-nano-emulsion syntheses. Raman spectroscopy and powder X-ray diffraction (PXRD) were employed to corroborate that the thermally treated particles under H2O : HNO3 (at 850 °C), H2O : NaOH (at 400 °C), and H2O : isopropanol (at 200 °C) yielded highly-pure rutile, anatase, and brookite phases, respectively. Herein, an experimental approach based on the PIT-nano-emulsion method is demonstrated to synthesize phase-controlled TiO2 particles with high purity employing fewer toxic compounds, reducing the quantity of starting materials, and with a minimum energy input, particularly for the almost elusive brookite phase.

Graphical abstract: Polymorphic control in titanium dioxide particles

Supplementary files

Article information

Article type
17 Jun 2022
22 Nov 2022
First published
23 Nov 2022
This article is Open Access
Creative Commons BY license

Nanoscale Adv., 2023,5, 425-434

Polymorphic control in titanium dioxide particles

G. Quiñones Vélez, D. Soto Nieves, A. Castro Vázquez and V. López-Mejías, Nanoscale Adv., 2023, 5, 425 DOI: 10.1039/D2NA00390B

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