Synthesis and Characterization of Manganese Oxide Octahedral Molecular Sieve and Its Catalytic Performance for DME Combustion

Manganese oxide octahedral molecular sieve (OMS-2) was prepared by the sol-gel method using KMnO4 and maleic acid in the presence of methoxypolyethylene glycols (MPEG) and used for the catalytic combustion of dimethyl ether (DME). XRD, FT-IR, and UV-Vis data confirmed the formation of cryptomelane-type manganese oxide. TEM results showed that OMS-2 had rod-like shape and MPEG played a role as a structure-directing agent in the OMS-2 formation. O2-TPD and H2-TPR results indicated that OMS-2 was rich in facile lattice oxygen, can activate oxygen, and can be easily reduced by H2. OMS-2 possessed excellent catalytic performance for DME combustion and can convert DME to CO2 and H2O at a relatively low temperature. The lattice oxygen played a key role in the DME combustion.