Activity and thermal stability of Pt/Ce0.64Mn0.16R0.2Ox (R=Al, Zr, La, or Y) for soot and NO oxidation

• Published in: Fuel processing technology Vol. 137; pp. 38 - 47
• Main Authors: Zhang, Hai-Long, Zhu, Yi, Wang, Shi-Dan, Zhao, Ming, Gong, Mao-Chu, Chen, Yao-Qiang
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.09.2015
• Subjects: CeO2-MnOx mixed oxides; NO oxidation; Platinum; Soot oxidation; Thermal stability; NO oxidation; Soot oxidation; Platinum; CeO2-MnOx mixed oxides; Thermal stability
• ISSN: 0378-3820; 1873-7188
• DOI: 10.1016/j.fuproc.2015.03.027

In this study, Al2O3, ZrO2, La2O3, and Y2O3 were separately introduced into Pt/CeO2-MnOx catalyst to improve the thermal stability of catalysts and obtain a better soot and NO oxidation activity after thermal treatment. CeO2-MnOx-ROx (R=Al, La, Y, or Zr) mixed oxides were prepared by a co-precipitation method. The catalysts were characterized by XRD, BET, H2-TPR, CO chemisorption, XPS, TG analysis, soot–TPO, and NO–TPO. It is found that the introduction of Rn+ into CeO2-MnOx markedly increases the thermal stability of the catalysts for soot and NO oxidation, remaining a better catalytic oxidation activity. On the one hand, after high-temperature aging, for the modified catalyst Pt/CeMnROx, the ignition temperature of soot oxidation (Ti) and maximal soot oxidation rate temperature (Tm) increase by 30–50°C and 4–32°C, respectively, whereas Al3+-modified catalyst shows the best thermal stability. On the other hand, due to a key role of NO2 as a strong oxidizing agent in soot oxidation process, the NO oxidation activity is often considered as an important aspect. This work shows that Rn+-modified catalysts display a better stability on NO oxidation activity after aging. Some factors leading to the thermal deactivation of catalysts are also discussed in this paper. •The introduction of Rn+ enhances the thermal stability of Pt/CeO2-MnOx.•The modified catalysts show better soot/NO oxidation activities after aging.•Al3+-modified catalyst shows the best thermal stability during soot oxidation.•The deactivation would be related to Mn and Pt species on the catalyst surface.