In situ PMMA-templating preparation and excellent catalytic performance of Co₃O₄/3DOM La_0.6Sr_0.4CoO₃ for toluene combustion

Rhombohedrally crystallized three-dimensionally ordered macroporous (3DOM) La_0.6Sr_0.4CoO₃ (LSCO)-supported Co ₃O₄ (x wt% Co₃O₄/3DOM LSCO; x = 0, 2, 5, 8, and 10) were prepared using the in situ poly(methyl methacrylate)-templating strategy. Physicochemical properties of the materials were characterized by means of numerous analytical techniques, and their catalytic activities were evaluated for the combustion of toluene. It is shown that the x wt% Co₃O₄/3DOM LSCO samples displayed a 3DOM architecture and a high surface area of 29-32 m²/g. Among the x wt% Co₃O₄/3DOM LSCO samples, the 8 wt% Co₃O ₄/3DOM LSCO sample possessed the highest adsorbed oxygen species concentration and the best low-temperature reducibility. The 8 wt% Co ₃O₄/3DOM LSCO sample showed the best catalytic performance for toluene combustion (the temperatures required for toluene conversions of 10, 50, and 90% were 158, 210, and 227 C at a space velocity of 20,000 mL/(g h), respectively). The apparent activation energies (43-58 kJ/mol) of the x wt% Co₃O₄/3DOM LSCO (x = 0-10) samples were lower than those (59-67 kJ/mol) of the 8 wt% Co₃O₄/bulk LSCO and bulk LSCO samples. It is concluded that the excellent catalytic performance of 8 wt% Co₃O₄/3DOM LSCO was associated with its high oxygen adspecies concentration, good low-temperature reducibility, and strong interaction between Co₃O₄ and LSCO as well as high-quality 3DOM structure.