Patent ID: 7431749
Filing Date: 2008-10-07
Classification: B01D,B01J,F01N,Y02A,Y02T,Y10S

Abstract:
1. A catalytic filter for removal of soot particulates from diesel engine exhaust, comprising: an oxidation catalyst positioned upstream of the catalytic filter, prepared by treating a PGM (platinum group metal) salt and a metal salt comprising a transition/alkali metal salt, Ba salt, or Mg salt with a water-soluble polymer compound and a reducing agent, to obtain a first colloidal mixture solution, which is then washcoated to a catalyst-support-coated monolithic ceramic substrate; and a catalyzed wall-flow filter positioned downstream of the catalytic filter, prepared by treating a PGM (platinum group metal) salt and a metal salt mixture including at least one catalyst metal selected from a first group consisting of Ba, Cr, Mn, Fe, Co, Ni, Cu, Mo, V and Pb to enhance oxidation activity and at least one catalyst metal selected from a second group consisting of Li, Na, K, Mg, Ca and Cs to decrease a combustion temperature of soot particulates, with a water-soluble polymer compound and a reducing agent, to obtain a second colloidal mixture solution, which is then washcoated on a catalyst-support-coated wall-flow filter.