LNT catalyst with enhanced nitrogen oxide storage capacity at low temperature

摘要

Disclosed is a lean NOx trap (LNT) catalyst with enhanced NOx storage capacity at low temperature. More particularly, an LNT catalyst with enhanced NOx storage capacity at low temperature and significantly inhibited thermal desorption is prepared by coating a washcoat on a honeycomb-type carrier and drying and baking the same. The washcoat contains a first catalyst powder in which barium (Ba) and a precious metal are supported on a ceria support, and a second catalyst powder in which a precious metal is supported on a magnesium (Mg)-substituted alumina support The LNT catalyst of the present invention is useful as a NOx reducing catalyst for a passenger diesel vehicle.

主权项

1. A lean NOx trap (LNT) catalyst comprising:
a washcoat which comprises a first catalyst powder and a second catalyst powder coated, dried and baked on a honeycomb-type carrier, wherein the first catalyst powder comprising barium (Ba) and a precious metal supported on a ceria support, and the second catalyst powder comprising a precious metal is supported on a magnesium (Mg)-substituted alumina support, wherein the LNT catalyst comprises about 55-70 wt % of the ceria support, about 20-35 wt % of the magnesium (Mg)-substituted alumina support, about 1-8 wt % of barium (Ba) and about 0.1-2 wt % of the precious metal, wherein the wt % are based on the total weight of the washcoat.