Flower-like Co3O4 Catalysts for Efficient Catalytic Oxidation of Multi-Pollutants from Diesel Exhaust

Nowadays, the oxidation activity at the low-temperature regime for Co3O4catalysts needs to be improved to meet the stringent regulation of multi-pollutant diesel exhaust. Herein, nanoflower-like Co3O4diesel oxide catalysts (DOCs) were fabricated with the addition of a low-content Pt to trigger better catalytic activities for oxidizing multi-pollutants (CO, C3H6, and NO) emissions by taking advantage of the strong-metal supporting interaction. Compared to the conventional DOCs based on Pt/Al2O3, the as-synthesized Pt/Co3O4catalysts not only exhibited better multi-pollutants oxidation activities at the low temperature but also obtained better resistance toward NO inhibition. Moreover, Pt/Co3O4catalysts showed exceptional hydrothermal durability throughout long-term tests in the presence of water vapor. According to the XPS and H2-TPR results, Pt promoted low-temperature catalytic activity by increasing the active surface oxygen species and reducibility due to the robust synergistic interaction between metallic Pt and supporting Co3O4. Meanwhile, TGA curves confirmed the Pt atoms that facilitated the desorption of surface-active oxygen and hydroxyl radicals in a low-temperature regime. Furthermore, instead of probing the intermediates during CO and C3H6oxidation for Pt/Co3O4catalysts, which included carbonates, formate, and acetate species, in situ DRIFTs experiments also revealed C3H6oxidation mainly took place over metallic Pt sites.Keywords:diesel oxide catalysts;catalytic oxidation;strong metal–support interaction;cobalt oxides;platinum