(674h) Influence of Engine Oil Derived Chemical Species on the Performance of Cu-SSZ-13 SCR Catalysts

Cu-SSZ-13 has been widely used as a commercial catalyst for selective catalytic reduction (SCR) of NO_x in diesel engine exhaust systems. In real world applications, the deactivation of Cu-CHA via chemical poisoning derived from different exhaust gas components, originating from biodiesel and engine oils for example, can be a durability issue for SCR catalysts, with literature showing that the accumulation of engine oil elements influences the catalyst’s physiochemical properties and can cause deactivation. Most of these studies introduce the poisoning element through an impregnation method. A focus of this work is to mimic real-world applications more closely by introducing the engine oil directly on the Cu-CHA zeolite and studying the impact of chemical species associated with engine oil on the performance of Cu-CHA.

In this study, real and surrogate engine oils were deposited on a commercial Cu-SSZ-13 catalyst using a simple dip method. For comparative study, the impact of the base oil with a surrogate with higher concentrations of additives was also studied. Results will be shown that describe the accumulation of different elements and their impact on activity. Those impacts will also be defined through different characterization studies, which reflect the change in physiochemical properties after oil exposure. Some oils were formulated with only one element to better decouple the effect of individual elements. High temperature experiments were run to evaluate if the catalysts could be regenerated after the oil exposures, and further confirmed that the accumulation of engine oil elements through multiple exposures could generate a stable species (metal oxides/ash/deposits) that causes irreversible poisoning.