Effects of hydrothermal aging on the sulfur poisoning of a Cu-SSZ-13 SCR catalyst

[Display omitted] •Synergistic effects of hydrothermal aging and S poisoning on Cu-SSZ-13 are studied.•Increasing aging duration results in decreased SCR reactivity.•Increasing aging duration prior S exposure reduces impacts of S poisoning.•Hydrothermal aging leads to the conversion of ZCuOH to Z2Cu in Cu-SSZ-13. Cu-SSZ-13 catalysts have been widely used for NOx reduction via SCR for diesel aftertreatment applications due to their high SCR efficiency. Hydrothermal aging and sulfur poisoning are two areas of research on Cu-SSZ-13 catalysts due to their significant relevance to real world applications. In addition to the effects of 650 °C hydrothermal aging, this work also investigates the corresponding sulfur poisoning effects upon aging. Hydrothermal aging results in decreasing SCR reactivity with constant activation energy. Upon sulfation at 400 °C, the catalyst displays decreasing SCR reactivity with lower activation energy. However, upon longer aging duration prior to sulfation, the decrease in SCR reactivity becomes less and the catalyst becomes more resistant toward sulfur poisoning with less sulfur loading. The enhanced sulfur poisoning resistance of Cu-SSZ-13 catalyst can be mainly ascribed to the gradual conversion of ZCuOH to Z2Cu upon aging as suggested by results from NH3 TPD and DRIFTS.