Kim YE  Byun MY  Lee KY  Lee MS

Vol. 28,  No. 2, pp. 147-153, Jun.  2022
10.7464/ksct.2022.28.2.147

Hydrothermal Methyl violet Photocatalyst Titanate nanotube

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Titanate nanotubes (TNTs) were synthesized via alkaline hydrothermal treatment using commercial TiO2 nanoparticles (P25). The TNTs were prepared at various TiO2/NaOH ratios, hydrothermal temperatures, and hydrothermal times. The synthesized catalysts were characterized by X-ray diffraction, field-emission scanning electron microscopy, N2 adsorption-desorption isotherms, field-emission transmission electron microscopy, and ultraviolet-visible spectroscopy. TNTs were generated upon a decrease in the TiO2/NaOH ratio due to the dissolution of TiO2 in the alkaline solution and the generation of new Ti-O-Ti bonds to form titanate nanoplates and nanotubes. The hydrothermal treatment temperature and time were important factors for promoting the nucleation and growth of TNTs. The TNT catalyst with the largest surface area (389.32 m2 g-1) was obtained with a TiO2/NaOH ratio of 0.25, a hydrothermal treatment temperature of 130 ℃, and a hydrothermal treatment time of 36 h. Additionally, we investigated the photocatalytic activity of methyl violet 2B (MV) over the TNT catalysts under UV irradiation and found that the degradation efficiencies of the TNTs were higher than that of P25. Among the TNT catalysts, the TNT catalyst that was hydrothermally synthesized for 36 h (TNT 36 h) exhibited a 96.9% degradation efficiency and a degradation rate constant that was 4.8 times higher than P25 due to its large surface area, which allowed for more contact between the MV molecules and TNT surfaces and facilitated rapid electron transfer. Finally, these results were correlated with the specific surface area.