Synthesis and Magnetic Properties of Cobalt Oxide Nanowires Array With Columnar SBA-15

Using hexagonal ordered straight-pore SBA-15 silica as hard template, mesoporous cobalt oxide (Co₃O₄) nanowires SBA-15 materials are synthesized by a nanoreplication route, and X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), field-emission scanning electron microscopy (FESEM), and N₂ physisorption isotherms are used to characterize the microstructure of columnar SBA-15 particles, Co₃O₄-doped SBA-15 (Co₃O₄/SBA-15) and Co₃O₄ nanowires array. The results indicate that Co₃O₄ exist in the mesochannels of SBA-15 to form Co₃O₄/SBA-15 nanocomposites and Co₃O₄ nanowires present mesostructure. Furthermore, the magnetic properties of Co₃O₄ nanowires array are measured and discussed by vibrating sample magnetometer (VSM) and surperconducting quantum interference device (SQUID), and the prepared Co₃O₄ nanowires array present superparamagnetism. Owing to surface effect of the uncompensated spins at the surface of Co₃O₄ nanowires, it presents a weak ferromagnetic behavior at low temperature.