A mullite oxide catalyst of SmMn2O5 for three-way catalysis: synthesis, characterization, and catalytic activity evaluation

Mullite oxide SmMn2O5 (SMO) was synthesized through a co-precipitation method. The CO + O-2 model system and more realistic gas mixtures were evaluated, and compared with perovskite LaCoO3 (LCO), SMO showed a better reaction activity as well as a higher catalytic activity and stronger hydrothermal resistance. Characterizations including XRD, BET, SEM, XPS, H-2-TPR, O-2-TPD, and CO + O-2 pulse were undertaken in order to gain insight into the origin of the SMO three-way catalytic activity. The lower adsorbed oxygen reduction temperature for SMO by H-2-TPR indicated a better reducibility. O-2-TPD suggested that SMO exhibited excellent mobility of beta-oxygen species. CO + O-2 pulse further revealed that the SMO catalyst had a better oxygen storage capacity than the LCO perovskite did. With a better reducibility, facile mobility of oxygen species and better oxygen storage capacity, mullite oxide SMO showed a preferable three-way catalytic activity.