Abstract: Nanometer MgO samples with high surface area, small crystal size, and mesoporous texture were synthesized by thermal decomposition of MgC2O4•2H2O, which was prepared by solid-state chemical reaction between H2C2O4•2H2O and Mg(CH3COO)2•4H2O. The existence of steam accelerated the sintering of MgO during the decomposition process and MgO with surface area as high as 412 m2/g was obtained through calcining the precursor in flowing dry nitrogen at 520 ℃ for 4 h. The samples were characterized by X-ray diffraction, N2 adsorption, transmission electron microscopy, thermogravimetry, and differential thermal analysis. The as-prepared MgO was composed of nanocrystals with a size of 4-5 nm and formed a wormhole-like porous structure. In addition, the MgO had good thermal stability, and its surface area was still 357 and 153 m2/g after calcination at 600 and 800 ℃ for 2 h, respectively. Compared with the MgO sample prepared by the precipitation method, MgO prepared by the solid-state chemical reaction has similar pore size distribution, surface area, and crystal size. The solid-state chemical method has the advantages of low cost, low pollution, and high yield; therefore it appears to be a promising method for the manufacture of nanometer MgO in industry.

Key words: nanometer magnesia, oxalic acid, magnesium acetate, solid-state chemical reaction, high surface area