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.