Effect of alternate CH4-reducing/lean combustion treatments on the reactivity of fresh and S-poisoned Pd/CeO2/Al2O3 catalysts

Insights into SO2 Interaction with Pd/Co3O4–CeO2 Catalysts for Methane Oxidation

“…Although the activity was not affected when cofeeding SO 2 in the reaction mixture at both k1 and k4 (Fig. 1b), some deactivation occurs during the SO 2 -free runs ( Table 3) likely due to spill-over of sulphate species from the fraction of Co 3 O 4 support to the portion of Pd not in contact with CeO 2 [16].…”

“…Based on literature results [16], after performing two SO 2 -free runs, regeneration by a CH 4 -reducing treatment at 600°C for 10 min was attempted over two selected catalysts, Pd/Co 3 O 4 and Pd/Co30Ce, in order to decompose sulphates; then a subsequent run, at k4, was recorded. Under these conditions only a partial regeneration took place for Pd/Co 3 O 4 (T 50 = 390°C), while the activity was completely restored for Pd/Co30Ce (T 50 = 322°C).…”

“…Among the sulphating supports it is worth to mention ceria which, due to the high basicity, leads to the formation of surface and bulk sulphates [15]. A protecting role of ceria from SO 2 poisoning of supported Pd has been evidenced over Pd/CeO 2 /Al 2 O 3 catalyst when palladium particles are in good contact with ceria [16]. In this study was also evidenced that sulphate species can be efficiently removed from the support by treatment at 600°C under CH 4 -reducing conditions.…”

Enhanced hydrothermal stability of high performance lean fuel combustion alumina-supported palladium catalyst modified by nickel

“…Catalytic combustion of lean methane has been extensively investigated during the last decades [1,2,5,[7][8][9]. The low concentration of methane [1,3] and a negative effect of water [10][11][12][13][14][15][16][17][18] are * Corresponding author.…”

“…The addition of promoters such as metal oxide to alumina-supported palladium catalysts could be useful to enhance both catalytic activity and stability. Several studies [7,17,[28][29][30][31][32][33][34][35][36][37][38][39] have investigated the catalytic activities of alumina supported palladium catalysts modified by oxide additives, such as ˛-Al 2 O 3 , Ce x Zr 1−x O 2 , Ni, Co, La, and Mg, which can enhance the activity and stability of catalyst. However, the problem of inhibition by water in the feed stream has not been solved, and little detailed study has been focused on the relationship between active sites and supports.…”