Macroporous SmMn 2 O 5 mullite for NO x -assisted soot combustion

• Published in: Catalysis science & technology Vol. 7; no. 4; pp. 838 - 847
• Main Authors: Feng, Zijian, Liu, Qinhan, Chen, Yongjie, Zhao, Pengfei, Peng, Qi, Cao, Kun, Chen, Rong, Shen, Meiqing, Shan, Bin
• Format: Journal Article
• Language: English
• Published: 2017
• ISSN: 2044-4753; 2044-4761
• DOI: 10.1039/C6CY02478E

A series of mullite SmMn 2 O 5 oxides were prepared by citric acid (CA), hydrothermal (HT) and co-precipitation (CP) and combustion of ethylene glycol and methanol solutions (EG&M) methods, and tested for NO x -assisted soot combustion. The catalyst performance tests were conducted under “loose” contact conditions and the physical and chemical properties characterized by XRD, FTIR, BET, SEM, XPS, and O 2 -TPD and H 2 -TPR measurements. The SmMn 2 O 5 -EG&M catalyst possessed a distinct morphology with slabs separated by interconnected macropores, and exhibited the overall highest catalytic activity for soot combustion. The corresponding T 10 , T 50 , and T 90 were 283 °C, 368 °C, and 420 °C, respectively, and the CO 2 selectivity was 99.6%. The soot combustion activation energy for the SmMn 2 O 5 -EG&M catalyst is 65 kJ mol −1 . O 2 -TPD and H 2 -TPR measurements demonstrated higher mobility and better reducibility of surface adsorbed oxygen for the EG&M sample. The soot combustion is greatly accelerated by the NO 2 -assisted mechanism under a NO + O 2 atmosphere and further enhanced by the interconnected macropores of the catalyst, facilitating an intimate contact between the soot and the catalyst. Our study reveals that SmMn 2 O 5 mullite is an effective catalyst for NO x -assisted soot combustion.