Formation of TiO2-Based Nanostructures via Alkaline Hydrothermal Treatment : Effect of Synthesis Parameters

Vollständiger Abstract

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Titanium dioxide (TiO2) is broadly applied as both a photocatalyst and an adsorbent for dye degradation. Textile dye wastewater contributes ~100 tons of pollutants annually, causing severe ecological damage even at trace concentrations. Conventional TiO2 photocatalysts suffer from rapid charge carrier recombination, while systematic studies linking hydrothermal synthesis parameters to morphology and controlled adsorbents remain limited. In this research, free-standing TiO2 nanostructures (FSTNS) were synthesized using an alkaline hydrothermal method to investigate their formation mechanism and performance in dye degradation. The synthesis parameter influenced certain structural characteristics, as well as the adsorption and photocatalytic performance of FSTNS. The FSTNS morphology was characterized by scanning electron microscopy (SEM) to assess the effects of hydrothermal duration (1 h, 5 h, 10 h, 15 h, 20 h, and 30 h) and NaOH concentration (2.5 N, 5 N, 7.5 N, and 10 N) at 180°C. The adsorption and photocatalytic performance of FSTNS were evaluated in a 30-ppm methylene blue (MB) solution under UV-C irradiation. Dye degradation was analysed using a UV-Vis spectrometer. The outcomes demonstrated that different hydrothermal times led to different morphologies, such as nanorods, nanosheets, and nanoribbons, each exhibiting excellent MB removal through adsorption alone or a combination of adsorption-photocatalysis pathways.