Morphology-steered synthesis of Ce-MnO2 catalysts for catalytic oxidation of ethane at low temperature

Abstract

Ce-MnO2 catalysts with nanosheets-stacked flower-like architecture were prepared by hydrothermal method, and Ce0.5Mn1 sample exhibited excellent catalytic performance for ethane combustion, with T90 at 310 °C. The apparent activation energy of the Ce0.5Mn1 sample (70.7 kJ mol−1) was comparatively lower than that of pure MnO2 (112.4 kJ mol−1). The formation of CeMn solid solution reduced the sizes of the Ce-MnO2 crystallites, affording higher SBET. Electron transfer and redistribution in the CeMn solid solution enhanced the activation of surface oxygen (OA) and generated more oxygen vacancies. The increasing OA species and highly mobile lattice oxygen boosted the oxidation of ethane. Also, the Ce0.5Mn1 catalyst exhibited enhanced H2O resistance with an ethane conversion over 95 % at 350 °C. Moreover, the morphologies of the CexMn1 catalysts were significantly influenced by Ce doping. Variations in Ce3+ amount significantly altered the thickness of the nanosheets, and the structure displayed more surface defects with considerable active sites. This work provides insights into the design of a promising MnO2-based catalyst for the mitigation of light alkanes.