Catalytic combustion of dimethyl ether over α-MnO2 nanostructures with different morphologies

Abstract Herein, α-MnO 2 catalysts with three well-defined morphologies (nanorod, ultra-long nanowire and microsphere) were rational designed and prepared by the hydrothermal route, and their catalytic activities were evaluated for the dimethyl ether (DME) combustion. These nanostructured α-MnO 2 catalysts were characterized in detail by various analytical techniques: XRD, FESEM, TEM, BET, XPS and H 2 -TPR. As a result, the α-MnO 2 nanorod exhibited the higher catalytic activity ( T 10  = 170 °C and T 90  = 238 °C at WHSV = 30,000 mL g −1  h −1 ) than the other two α-MnO 2 samples due to its larger specific surface area, higher average oxidation state of Mn, more abundant surface lattice oxygen (O latt ) species and higher reducibility, and there was no obvious decrease after the α-MnO 2 nanorod was run for 50 h. Moreover, the transient response technique revealed that the O latt species of the α-MnO 2 nanorod should be the crucial role in the deep oxidation of DME.