Emission control catalyst article with enriched pgm zone, method and apparatus to produce the same

Abstract

The presently claimed invention provides an emission control catalyst article comprising a substrate having an inlet axial end and an outlet axial end, a bottom washcoat layer coated on the 60 to 100% length of the substrate from the inlet axial end to the outlet axial end, and a top washcoat layer coated on the 60 to 100% length of the substrate from the inlet or the outlet or both end of the substrate such that the top coat covers at least 60% of the length of the bottom washcoat layer, wherein at least part of the top washcoat layer and/or the bottom washcoat layer comprises a first portion and a second portion, wherein the first portion begins at the inlet axial end or the outlet axial end of the substrate and exhibits a platinum group metal concentration of 2 to 100 times higher than the concentration of a platinum group metal in the second portion, wherein the first portion comprises 5-50% of the substrate volume and exhibits a three-dimensional axial and/or radial zone arrangement starting from the inlet axial end of the substrate or the outlet axial end or both, wherein the platinum group metal loading in the first portion is 10 to 1000 g/ft, as determined axially from a first end of the first portion to a second end of the first portion. The platinum group metal of the first portion is deposited by spraying a platin group metal precursor solution using an apparatus comprising a spray nozzle connected to the dosing unit via a second supply tube, a control arm device connected to the spray nozzle, wherein said control arm device is adapted to allow the 3-D positioning of the nozzle relative to a substrate face and adapt the radial and/or axial deposition of the platinum group metal within the individual channels.