Structure and magnetic properties of Co-doped TiO2 nanotubes by aqueous solution method

The Co-doped titanium dioxide nanotubes were synthesized via the aqueous solution reaction. After hydrogenation, room temperature ferromagnetism (RTFM) was found in the cobalt doped titanium dioxide nanotubes at 300 K by the vibrate sample magnetometer. As the concentration of cobalt increased, the observed ferromagnetism became stronger. The X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy and energy dispersive X-ray spectroscopy were performed and excluded the existence of cobalt cluster. Therefore, the magnetic ions and oxygen vacancies induced by hydrogenation contribute to the observed ferromagnetism at 300 K.