Urea-selective catalytic reduction (SCR) has evolved to become the emission control technology of choice for NOx control on many diesel-powered vehicles. As part of this transformation, the thermal stability of zeolite-based SCR catalysts has been established for both light-duty and heavy-duty applications. Most recently, the low temperature activity and durability of Cu-based zeolite technology has been demonstrated.
As has been observed on other platforms, packaging and performance requirements often dictate the use of different substrate materials for the support of emission control catalysts. As urea-SCR technology is introduced to a broader range of engines and equipment, options related to substrate compatibility become ever more important.
In this paper, the urea-based SCR activity of a Cu-based zeolite catalyst is evaluated when supported on a range of ceramic and metallic substrates. Results as a function of exhaust temperature and space velocity for substrates differing in cell density, wall thickness, and in the case of certain metallics, also foil structure are summarized.