Low-Temperature Combustion of Toluene over Cu-Doped SmMn2O5 Mullite Catalysts via Creating Highly Active Cu2+–O–Mn4+ Sites

Catalytic combustion of volatile organic compounds (VOCs) at low temperatures is still an urgent issue to be solved. Herein, low-temperature combustion of toluene over Cu-doped SmMn2O5 mullite catalysts via creating highly active Cu2+-O-Mn4+ sites has been originally demonstrated. Cu-doped SmMn2O5 mullite catalysts exhibited 90% conversion of toluene at 206 °C and displayed robust stability even in the presence of water. It has been demonstrated that Cu doping created Cu2+-O-Mn4+ active composite sites that were more exposed after removing surface Sm species via acid-etching. Benefiting from this, the redox and oxygen activation ability of catalysts was significantly enhanced. The consumption of benzaldehyde and benzoic acid as intermediate species and the CO2 generation ability were apparently promoted, which were the direct reasons for the enhanced low-temperature combustion of toluene. This work provides novel ideas for the development of high-performance catalysts for low-temperature VOC combustion, which has great industrial application prospects.