(600b) Characteristics of Pt-K/MgAl2O4 NOx Storage-Reduction Catalysts


Although the lean burn engines are considered as a promising solution for obtaining high fuel efficiency, however, there are challenges in their catalytic aftertreatment system, especially due to selectively reduce nitrogen oxides (NOx) in the net oxidizing environment.  Lean NOx trap (LNT) catalysts are generally regarded as one of the potential options for removing NOx in the diesel engine exhaust.  In the LNT technology, alkali or alkaline earth elements (K or Ba) take up NOx under lean operation and store them as nitrates, which are subsequently reduced during rich operation [1].  Ba is primarily used for storing NOx at low temperature, while K is at high temperature.  It was reported that MgAl2O4 support promotes the shift of the maximum NOx uptake toward the higher temperature.  Therefore, Pt-K/MgAl2O4 catalyst demonstrated the excellent activity at higher temperature [2].  However, the detailed study about the effects of K loading, thermal aging and SO2 poisoning on the activity of MgAl2O4 supported catalyst is not clear yet.  In this contribution, we try to understand the characteristics of Pt-K/MgAl2O4 catalysts, especially focusing on the role of MgAl2O4 support in NOx storage-reduction processes, compared with Al2O3 supported one.


  1. Roy S. and Baiker, A. Chem. Rev. 109, 4054 (2009).
  2. Takahashi, N., Matsunaga, S., Tanaka, T., Sobukawa, H. and Shinjoh, H. Appl. Catal. B 77, 73 (2007).