| 摘要 |
A catalytic article comprises a substrate having an inlet and outlet, coated with a 1st coating comprising a blend of platinum on a support with low ammonia storage with a 1st SCR catalyst and a 2nd coating comprising a 2nd SCR catalyst; where the 2nd coating at least partially overlaps the 1st coating. The 1st SCR catalyst is a Cu-SCR or Fe-SCR catalyst. The 2nd coating may completely overlap the 1st coating, or the 2nd coating may overlap at least 20% if the 1st coating. The Pt blend can further comprise Pd, Au, Ag, Ru or Rh. The Fe or Cu in the 1st SCR catalyst may be loaded on a molecular sieve, preferably with a BEA or MFI framework. The 2nd SCR catalyst is also a base metal such as V, Mo, W, Cr, Ce, Mn, Fe, Co, Ni or Cu supported on a molecular sieve, and it may also include promoted Ce-Zr or MnO2. The substrate can be cordierite, an extruded honeycomb or filter. Further aspects relate to a method of treating exhaust gas comprising N2 and NH3 using the catalytic article, and improving the N2 yield from NH3 and NOx from 200 to 350 °C. |
