Interfacial engineering enables surface lattice oxygen activation of SmMn2O5 for catalytic propane combustion

Abstract

Surface lattice oxygen (Olatt) over transition metal oxides plays a pivotal role in catalytic combustion of automobile exhaust. The insufficient Olatt activity at low temperatures, however, remains the key problem restricting its practical application. To overcome this deficiency, we activated the Olatt of mullite SmMn2O5 through the interface fabrication with spinel Co3O4. The optimized Co3O4/SmMn2O5 catalyst exhibited 90% conversion at 247 °C for the typical automobile exhaust propane combustion, 77 °C lower than the original SmMn2O5. Additionally, Co3O4/SmMn2O5 showed extremely high stability even under harsh operating temperature (e.g., 800 °C). Experimental and theoretical calculation results revealed that the regulated interface of Co3O4/SmMn2O5 facilitated the electrons transfer from SmMn2O5 to Co3O4, contributing to the enhanced propane adsorption and catalytic oxidation activity due to the formation of electrophilic oxygen in SmMn2O5 around the interface. This work can provide a basic understanding of the Olatt activation for developing efficient automobile exhaust combustion catalysts.