Synthesis of MgO microspheres with nanosheets in a mechanical force reactor and its optical property

MgO microspheres with leaf-like nanosheets structure were prepared by direct carbonation of calcined magnesite in a mechanical force reactor. XRD analysis indicates that the products is cubic MgO structure with a lattice constant of a = 0.421 nm. Its average diameter of MgO microsphere is in the range of 10–40 μm, and leaf-like nanosheets with thickness of 20–50 nm is single crystalline by SEM and TEM observation. By comparing SEM images of MgO microspheres and basic magnesium carbonate, microsphere structure has been formed during the thermal decomposition process of Mg(HCO3)2 aqueous solution, and not damaged during the formation of MgO at the temperature of 800 °C. The formation mechanism of MgO microspheres with nanosheets was proposed in this paper. Photoluminescence property of MgO product was investigated, showing that emission peak at 335 nm was related to new energy levels induced by defects or defect levels generated.