Gas treatment device comprising SMSI material and methods for making and using the same

Since the advent of emissions standards for internal combustion engines for cars, trucks, and other vehicles, emissions of hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NO ) have markedly declined. This decline has been brought about through the use of a variety of techniques including electronic fuel injection, electronic engine control, and the use of a variety of catalytic converters to oxidize HC and CO, and to reduce NO to nitrogen. However, increasingly more stringent emissions standards require even less pollutants in the gas emissions over extended periods of engine operation. A gas treatment device, comprises a substrate disposed within a shell. The substrate comprises a catalyst composition comprising a support, a catalyst, and a sufficient amount of SMSI material such that, upon exposure to a gas stream (at a gas treatment device operating temperature), less than or equal to about 35 wt % of hydrocarbons in the gas stream are burned.A method for forming a gas treatment device, comprises applying a slurry to a substrate, wherein the slurry comprises a support and a sufficient amount of SMSI material such that, upon exposure to a gas stream at a gas treatment device operating temperature, greater than or equal to about 50 wt % of hydrocarbons in the gas stream are cracked to a light fraction; applying a catalyst to the substrate; calcining the catalyst; and disposing the calcined substrate into a shell, with a retention material disposed between the shell and the calcined substrate.