Synergistic promotion effect of MgO and CeO2 on nanofibrous Ni/Al2O3 catalysts for methane partial oxidation

Abstract

Ni/Al2O3 catalysts are formed via NiAl2O4 reduction while inactive NiAl2O4 is readily re-formed in the presence of oxidant agent during reactions, such as oxygen in methane partial oxidation. MgO has demonstrated promotion effect through securing Al2O3 to form MgAl2O4 during catalyst calcination so as to diminish NiAl2O4 formation. However, the promotion effect is limited by the formation of NiO-MgO solid solution with low reducibility. CeO2 promotes NiAl2O4 reduction via forming CeAlO3 and therefore prevents NiAl2O4 re-formation during the reaction. This study, for the first time, demonstrates the synergistic promotion effect of MgO and CeO2 on the Ni/Al2O3 catalysts for methane partial oxidation through optimizing MgO and CeO2 contents in the MgO-CeO2-Ni/Al2O3 catalyst system. The thermally stable structure of fibrous catalysts prepared by one-step electrospinning enables the investigation of the synergistic promotion.