Preparation of Nanometer Magnesia with High Surface Area and Study on the Influencing Factors of the Preparation Process

Three kinds of MgC2O4·2H2O were prepared by the precipitation method with different raw materials, and MgO with high surface area was obtained via thermal decomposition of MgC2O4·2H2O in different atmospheres. The precursor MgC2O4·2H2O and as-prepared MgO were characterized by XRD, BET, TEM, and TG-DTA measurements. It was found that using Mg(CH3COO)2·4H2O and H2C2O4·2H2O as the starting materials and calcining the precursor MgC2O4·2H2O in flowing dry gas are the key factors to obtain high surface area for MgO. The MgO prepared at the optimum condition is composed of nanocrystals with a size of about 4-5 nm and forms a wormhole-like porous structure with a specific surface area of 534 m2·g−1 after calcining at 520 °C. In addition, the MgO has good thermal stability; after being calcined at 650 °C and 800 °C for 2 h, its surface area is still 229 m2·g−1 and 134 m2·g−1, respectively.