• Title/Summary/Keyword: Hydrothermal synthesis

Search Result 541, Processing Time 0.042 seconds

Synthesis of AlO(OH) Nano Colloids from γ-Al2O3 via Reversible Process (γ-Al2O3로부터 가역과정을 경유한 AlO(OH) 나노콜로이드의 합성)

  • Cho, Hyun-Ran;Kim, Sook-Hyun;Park, Byung-Ki
    • Journal of the Korean Ceramic Society
    • /
    • v.46 no.3
    • /
    • pp.288-294
    • /
    • 2009

  • The platelet AlO(OH) nano colloids were prepared by hydrothermal reaction of the $\gamma-Al_2O_3$ obtained with dehydration of $\gamma$-AlO(OH) and dilute $CH_3COOH$ solution. In hydrothermal reaction process, reversible reaction was accompanied between $\gamma-Al_2O_3$ and AlO(OH), and hydrothermal reaction temperature, hydrothermal reaction time and $CH_3COOH$ concentration had an effect on the crystal structure, surface chemical property, surface area, pore characteristics and crystal morphology of the AlO(OH) nano colloid particles. In this study, it was investigated to the hydrothermal reaction condition of the AlO(OH) nano colloid for using catalyst support, heat resisting agent, adsorbents, binder, polishing agent and coating agent. The crystal structure, surface area, pore volume and pore size of the platelet AlO(OH) nano colloids were investigated by XRD, TEM, TG/DTA, FT-IR and $N_2$ BET method in liquid nitrogen temperature.

  • https://doi.org/10.4191/KCERS.2009.46.3.288 인용 PDF KSCI

Synthesis of Titanate Nanotubes Via A Hydrothermal Method and Their Photocatalytic Activities

  • Kim, Ye Eun;Byun, Mi Yeon;Lee, Kwan-Young;Lee, Man Sig
    • Clean Technology
    • /
    • v.28 no.2
    • /
    • pp.147-154
    • /
    • 2022

  • 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.

  • https://doi.org/10.7464/ksct.2022.28.2.147 인용 PDF KSCI