Construction of Cu-SSZ-13@SAPO-34 selective catalytic reduction catalyst: Multifunctional protective shell against hydrothermal aging and chemical poisoning

Cu-SSZ-13, a Cu-exchanged zeolite, has been applied as a NO x selective catalytic reduction (SCR) catalyst for diesel aftertreatment, but improving its durability remains a challenge. To address this issue, a core–shell Cu-SSZ-13@SAPO-34 catalyst was prepared by a microwave-assisted hydrothermal method. The evolution of copper species and zeolite framework during high-temperature hydrothermal aging, potassium poisoning and sulfur poisoning, as well as the impacts on SCR performance, was explored. Cu 2+ ions detached by hydrothermal aging could migrate from the Cu-SSZ-13 core to the SAPO-34 shell and be reactivated, owing to the close interface contact between the zeolites. When exposed to chemical poisoning by K + and SO 2 , the SAPO-34 shell effectively shielded the Cu-SSZ-13 core. Thus, more active Cu 2+ ions could be preserved to maintain the SCR performance of the catalyst.