Catalytic combustion of toluene with La0.8Ce0.2MnO3 supported on CeO2 with different morphologies

Different morphologies of nano-CeO2 (rod, cube, and polyhedron) were successfully prepared by the hydrothermal method. La0.8CeO2MnO3 catalysts were deposited on the surface of these CeO2 to obtain La0.8Ce0.2MnO3/CeO2 catalysts. The catalytic activity of these materials was tested for toluene catalytic combustion, and the role of nano-CeO2 morphology on the catalyst activity was investigated. It was found that the morphology of CeO2 had a great effect on the activity of La0.8Ce0.2MnO3. La0.8Ce0.2MnO3/CeO2 nanopolyhedra exhibited the best activity at both low-temperature and high-temperature; the ignition temperature and complete conversion temperature were 128 and 240 degrees C, respectively. The relationship between the structural properties of different morphologies CeO2 and the catalyst activity was investigated by scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), Brunauer-Emmett-Teller (BET) and H-2-temperature programmed reduction (H-2-TPR). The higher catalytic activity of La0.8Ce0.2MnO3/CeO2 nanopolyhedra was attributed to high specific surface area, small grains, more oxygen vacancies, and highly reactive oxygen species. La0.8Ce0.2MnO3/CeO2 nanorods had poor low temperature activity because of high reduction temperature; La0.8Ce0.2MnO3/CeO2 nanocubes had higher hydrogen consumption, but the smaller specific surface area limited the catalytic activity. (C) 2016 Elsevier B.V. All rights reserved.