Synthesis of ilmenite-derived TiO2 photocatalysts with different morphologies: Enhanced photocatalytic activity using ammonium hexafluorotitanate

초록

"There is an increasing need for affordable methods to produce efficient TiO2 photocatalysts for degrading organic pollutants. In this study, we introduced a novel approach by using ammonium hexafluorotitanate (AHFT) obtained from the pyrolysis of ilmenite as a precursor for the preparation of titanium dioxide (TiO2) nanoparticles (NP), hollow spheres (HS), and hierarchical nanostructures via wet precipitation. We evaluated the morphological characteristics and photocatalytic activity of the synthesized TiO2 NP under UV irradiation using various methods. Among the structures we synthesized, TiO2 HS exhibited superior photocatalytic efficiency. This was due to its enhanced charge carrier separation, increased light absorption, and reduced electron-hole recombination facilitated by surface-adsorbed fluorine ions. In addition, TiO2 HS exhibited superior photocatalytic performance, achieving 86 % photodegradation efficiency under UV light, which was attributed to its high specific surface area (110 m2/g), mesoporous structure and surface fluorine ions facilitating charge separation. Moreover, our findings demonstrate the excellent stability and reusability of TiO2 HS, maintaining 84 % of its initial photocatalytic activity after three cycles. Trapping experiments revealed hydroxyl radicals (∙OH) and superoxide radicals (∙O2−) as the main reactive species, reducing photocatalytic efficiency by 34.6 % (∙OH) and 36.9 % (∙O2−). This study highlights the potential of AHFT as a precursor for the morphology-controlled synthesis of TiO2, particularly in the context of photocatalysts. It emphasizes the promising applications of this approach in addressing the increasing demand for cost-effective methods in this field, highlighting the potential of the novel method. © 2025 Elsevier Ltd and Techna Group S.r.l.

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