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Bulletin of Chemical Reaction Engineering and Catalysis, Volume 12, Issue 1, 2017, pp. 71-80

Simultaneous elimination of soot and NOX through Silver-Barium based catalytic materials

Abstract :

In this research paper, the nanometric size effect, the effects of the intrinsic factors including structure, and the redox properties of three systems of nanometric of silver-based catalysts were summarized. In this work, these catalysts were investigated for the simultaneous removal of particulate matter (diesel soot), and NOX was compared with that of a model of Pt-Ba/Al2O3 catalyst. The Silver-Barium based catalytic materials of Ag (5 wt%)-Ba(10 wt%)/MO (MO=Al2O3, CeO2, ZrO2,) and Ag (5 wt%)-Sr (10 wt%)/CeO2 catalysts have been prepared by wetness impregnation method and characterized by BET, XRD, HRTEM, and TPR (temperature-programmed reduction) experiments. The behavior of the catalyst in the soot combustion (under tight conditions) and NOX elimination has been separately analyzed by means of temperature programmed oxidation and isothermal concentration step change experiments, respectively. The results showed that all the catalysts were active in soot combustion with an indicative decrease of oxidation onset temperature compared to uncatalyzed soot oxidation. The removal of NOX in the presence and in the absence of soot was investigated under cycling conditions, i.e. alternating lean-rich phases according to the LNT approach. It has been found that the Ag-based samples were able to simultaneously remove soot and NOX. In particular, studying the behavior of the prepared catalysts, the Ba-containing systems exhibited higher NOX storage capacity than Sr-catalyst; also, the nitrogen selectivity increased even if resulted lower than the traditional LNT Pt-based catalyst. An adverse effect of soot on the NOX storage activity has been also observed. 

Keywords : Catalysts,Diesel soot oxidation,LNT,Silver barium,Simultaneous removal
Subject Area : Catalysis Process Chemistry and Technology

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