SO2 adsorption and desorption characteristics of bimetallic Pd-Pt catalysts: Pd: Pt ratio dependency

SO2 adsorption and desorption, and species formed, on Pd/Pt bimetallic, gamma-Al2O3 supported catalysts were characterized as a function of Pd/Pt ratio using DRIFTS and TPD studies. Catalysts with a high Pd content tended to form a greater amount of aluminum sulfate species, which decomposed at high temperature. In contrast, low Pd content catalysts tended to form a greater amount of low-temperature decomposing and desorbing species, such as molecular SO2 and alumina surface sulfite. The amount of SO2 adsorbed and later desorbed during TPD decreased with increasing Pt content in the bimetallic Pd-Pt/Al2O3 catalysts.