Construction of multifunctional interface engineering on Cu-SSZ-13@Ce-MnO_x/Mesoporous-silica catalyst for boosting...

Although small pore Cu-SSZ-13 catalysts have been successful as commercial catalysts for controlling NO_x emissions from mobile sources, the challenges of high light-off temperature, SO₂ tolerance and hydrothermal stability still need to be addressed. Here, we synthesized a multifunctional core-shell catalyst with Cu-SSZ-13 as the core phase and Ce-MnO_x supported Mesoporous-silica (Meso-SiO₂) as the shell phase via self-assembly and impregnation. The core-shell catalyst exhibited excellent low-temperature activity, SO₂ tolerance and hydrothermal stability compared to the Cu-SSZ-13. The Ce-MnO_x species dispersed in the shell are found to enhance both the acidic and oxidative properties of the core-shell catalyst. More critically, these species can rapidly activate NO and oxidize it to NO₂, which allows the NH₃-SCR reaction on the core-shell catalyst to be initiated in the shell phase. Meanwhile, Ce-MnO_x species can react preferentially with SO₂ as sacrifice components, effectively avoiding the sulfur inactivation of the copper active sites. Furthermore, the hydrophobic Meso-SiO₂ shell provides an important barrier for the core phase, which reduces the loss of active species, acid sites and framework Al of the aged core-shell catalyst and mitigates the collapse of the zeolite framework. This work provides a new strategy for the design of novel and efficient NH₃-SCR catalysts.