Characterization and Photoluminescence Properties of MgO Microtubes Synthesized from Hydromagnesite Flowers

Monoclinic hydromagnesite (Mg-5(CO3)(4)center dot(OH)(2)center dot 4H(2)O) flower-like structures of 2-3 mu m diameter have been synthesized at room temperature by a simple precipitation method without using any template, catalyst, or surfactant. The as-synthesized flowers were further calcined at various temperatures to prepare monodispersed, nanofibrous MgO microtubes of aspect ratio similar to 15. Both the precursor flowers and the MgO microtubes formed were characterized by powder XRD, TG-DTA, FT-IR, SEM, EDAX, HR-TEM, SAED, BET analysis and photoluminescence (PL) studies. A plausible mechanism for the formation of cubic MgO microtubes from monoclinic hydromagnesite flowers is proposed. The as-synthesized nanofibrous MgO microtubes have shown intense green and red emission. The more defective MgO microtubes formed in N-2 atmosphere at 400 degrees C showed the highest PL intensity and surface area. An attempt has been made to correlate the lattice parameter and the PL intensity.