Surface Modification of Metal Oxide Nanoparticles during Supercritical Hydrothermal Synthesis

Abstract

In situ production and surface modification of cobalt oxide nanoparticles and titanium oxide nanoparticles were carried out by hydrothermal synthesis in subcritical and supercritical water condition at 200, 300 and 400°C. In order to modify the surface of these metal oxides, several modifiers as CH₃(CH₂)₅OH, CH₃(CH₂)₄CHO, CH₃(CH₂)₄COOH and CH₃(CH₂)₅NH₂ were examined. By using the Fourier transform infrared spectra for investigation of modified surfaces, it was found that, these modifiers can modify the surface of cobalt oxide nanoparticles. The surface of titanium oxide nanoparticles are also modified by these reagents. Crystalline structure and size of synthesized nanoparticles were studied by using X-ray diffractometer patterns and transmission electron microscopy, respectively.