• Title/Summary/Keyword: chemical oxide

Search Result 3,456, Processing Time 0.026 seconds

Hydrothermal Synthesis of Mesostructured Vanadium Oxide and Application of UV-Ozone Treatment

  • Chang, Ju-Yeon;Jung, Duk-Young
    • Bulletin of the Korean Chemical Society
    • /
    • v.24 no.5
    • /
    • pp.613-616
    • /
    • 2003
  • Effect on hydrothermal treatment of lamellar vanadium oxides was investigated and the formation of hexagonal and cubic mesophase was found. This lamellar materials were prepared by mixing of cetyltrimethylammonium-bromide and pH-controlled sodium metavanadate solution. Thermal method and UV/O₃treatment were applied to extract organic template. The structure of resulting product was studied by powder X-ray diffraction and transmission electron microscopy (TEM).

Voltammetric Behaviors of Chemically Modified Electrodes Based on Zirconium Phosphonate Film

  • 홍훈기
    • Bulletin of the Korean Chemical Society
    • /
    • v.16 no.9
    • /
    • pp.886-891
    • /
    • 1995
  • Electroactive monolayers based on zirconium(Ⅳ) phosphonate film were prepared on gold and tin oxide electrodes by sequential layer-by-layer depostion technique. High transfer coefficient values and surface coverages of surface bound redox molecules were obtained from the electrochemical measurements of heterogeneous electron transfer rates for monolayer modified electrodes. 1,10-Decanediylbis(phosphonic acid) (DBPA) monolayer as insulating barrier was effective in blocking electron transfer. However, these film modified oxide electrode shows voltammetric behavior of diffusion/permeation process taking place at very small exposed area of modified electrode through channels due to structural defects within film when a very fast redox couple such as Ru(NH3)63+ is hired.

Influence of Amphoteric Behaviour of Oxide Materials on the Selectivity of Micro and Mesoporous Ceramic Membranes

  • L. Cot;A. Larbot
    • Bulletin of the Korean Chemical Society
    • /
    • v.18 no.9
    • /
    • pp.1028-1031
    • /
    • 1997
  • Electrostatic interaction is a very important parameter for the membrane selectivity. In this work, the electrical double layer establishment on the surface of metal oxide material from the Stern-Grahame model has been described. Then, some examples of rejection using micro and mesoporous ceramic membranes have been given. A correlation between the charges of the membrane material and the species to be filtered has been precised. Two rejection mechanisms have to be taken into account the size of the solutes and the electrostatic interactions.