Solvothermal Synthesis of CoO, Co₃O₄, Ni(OH)₂ and Mg(OH)₂ Nanotubes

In this paper, CoO, Co 3 O 4, Ni(OH) 2, and Mg(OH) 2 nanotubes were synthesized by solvothermal treatment of corresponding colloidal hydroxide. These nanotubes were characterized by powder X-ray diffraction (XRD), selected area electron diffraction (SAED), and transmission electron microscopy (TEM). According to the time-dependent morphology evolution, it is likely that the growth is governed by a solution−solid process. Advantages of this method include that it is a simple and general process without the need for a catalyst, surfactant, or template, which makes it low cost, and that the raw materials are readily available. On the basis of the above results, other metal hydroxides with layered structure are therefore potentially capable of forming nanotubes.