Synthetic effect on Ce/Pd@MFI OXZEO catalysts for methane combustion with excellent sulfur resistance

Although palladium-based catalysts exhibit excellent methane oxidation activity, sulfur poisoning still leads to severe deactivation. To overcome this, we synthesized an oxide-zeolite (OXZEO) composite, Ce x /Pd@MFI, via combined hydrothermal treatment and ball milling . In the resulting architecture, PdO x active sites are spatially confined within the MFI framework, while CeO 2 nanoparticles uniformly decorate the external surface as protective species. The optimized Ce 3 /Pd@MFI catalyst demonstrated markedly enhanced sulfur resistance, achieving a T 50 —the temperature at which 50 % CH 4 conversion occurred—of 361 °C after sulfation with 100 ppm SO 2 . Moreover, Ce 3 /Pd@MFI maintained sulfur-resistant stability for 110 h, far surpassing Pd@MFI and Pd/Al 2 O 3 , which rapidly deactivated upon exposure to SO 2 for bare 1 h. Furthermore, we proposed a redox-atmosphere switching method to regenerate sulfated CeO 2 protective species, thereby enabling the Ce x /Pd@MFI catalysts to maintain durable sulfur tolerance. The broad applicability of the OXZEO design was further confirmed in CO oxidation : Ce 3 /Pd@MFI remained stable under high SO 2 concentrations during CO oxidation. This work establishes a paradigm for engineering sulfur-resistant palladium catalysts via synergistic spatial confinement and protective-site incorporation, offering critical insights for the development of robust emission-control catalysts in sulfur-rich environments.