Promotion of Low-Temperature Oxidation of Propane through Introduction of Ce into Mullite Oxide YMn O.

A high-surface-area Ce doped mullite YMn O was developed via a facile hydrothermal approach, which exhibited higher catalytic activity with a long thermal stability towards propane oxidation in regards to pristine mullite YMn O . T (the temperature at 90 % conversion of reactant) of propane over the mixed oxides is ∼40 °C lower than that over pristine YMn O mullite (147 m /g). The complete oxidation temperature occurs at as low as 225 °C (1000 ppm C H and 10 % O balanced with N , WHSV=30,000 mL/g h). Notably, the mixed oxides maintain superior catalytic stability at 250 °C for 120 h without noticeable loss in the activity. Fundamentally, the remarkable performance stems from the abundant oxygen defects caused by the lattice mismatch between CeO and YMn O , which is conducive to the gas phase oxygen adsorption and activation, thereby enhancing the low temperature catalytic activity of the material. In addition, the CeO on the catalyst's surface acts as an oxygen reservoir and provides additional adsorption sites for propane to promote the oxidation reaction. In situ DRIFTS results indicates that the dissociation of acrylate could be the key step for propane oxidation since acrylate is more difficult to decompose and desorb than formate and acetate. These findings revealed the roles of ceria on mullite oxides for propane oxidation activity.