Rational Design of Ru-CeO 2 /Al 2 O 3 Composite Catalysts: Insight into Special Catalytic Behavior in Dimethyl Disulfide Oxidation

The serial Ru/CeO 2 /Al 2 O 3, CeO 2 /Ru/Al 2 O 3, and Ru-CeO 2 /Al 2 O 3 catalysts were successfully prepared for dimethyl disulfide (DMDS) catalytic combustion, in which the deposition sequence of CeO 2 and Ru was well regulated. Among these catalysts, the Ru-CeO 2 /Al 2 O 3 showed the highest activity ( T 90 = 275 °C), stability and sulfur resistance for DMDS oxidation. It revealed that the simultaneous introduction of CeO 2 and RuO 2 results in the smallest grain size and highly dispersed CeO 2 and RuO 2 . And the superior performance should be attributed to the excellent low-temperature redox capacity and high concentrations of oxygen defects, which was originated from the strong interaction between Ru species and CeO 2 . Besides, in situ FTIR and regeneration experiments revealed that the main cause of catalyst sulfur deactivation was sulfur deposition on the catalyst surface, reversible inactivation could be restored by an increase of reaction temperature. This study provides a reference for the rational design and adjustment of catalyst structures.