A template-free, thermal decomposition method to synthesize mesoporous MgO with a nanocrystalline framework and its application in carbon dioxide adsorption.

Alk. earth-based oxides are important materials for CO2 storage. A template-free method to synthesize meso-porous MgO by thermal decompn. of anhyd. magnesium acetate is presented. Characterization of cryst. phase, particle and pore sizes, and surface area for mesoporous MgO was done using a variety of techniques: SEM, high resoln. transmission electron microscopy, powder x-ray diffraction, and N2 adsorption anal. Results showed meso-porous MgO synthesized from anhyd. magnesium acetate had a high surface area (120-136 m2/g) and a narrow pore size distribution (3-4 nm). The pore was comprised of small, primary MgO nano-particle aggregates with inter-particle connections. In-situ transmission Fourier transform IR spectroscopy assessed CO2 adsorption by meso-porous MgO. This spectroscopic assessment showed meso-porous MgO exhibited enhanced CO2 adsorption capacity vs. com. available MgO nano-particles. This difference was mainly attributed to increased surface area. Differences in surface carbonate/bicarbonate speciation, obsd. between meso-porous and com. MgO, were related to structural differences of the smaller nano-particles. [on SciFinder(R)]