Chlorine-Tolerant Chlorobenzene Combustion over Mullite Catalysts via <i>In Situ</i> Constructing Ru–O–Mn Sites

Abstract

The catalytic combustion of chlorine-containing volatile organic compounds (CVOCs) at low temperatures still faces chlorine poisoning challenges. Herein, chlorine-tolerant chlorobenzene combustion over manganese-based mullite (SmMn₂O₅) catalysts has been originally demonstrated via <i>in situ</i> constructing rich Ru-O-Mn sites, engineered from the <i>in situ</i> doping of ruthenium (Ru) and the subsequent etching of samarium (Sm). Such catalysts exhibited 90% activity for chlorobenzene combustion at 258 °C and maintained about 80% activity after the 30 h stability test. Specifically, the doping of Ru could readily replace Mn⁴⁺ of SmMn₂O₅ to form Ru-O-Mn sites, and the etching of Sm could expose more surface Ru-O-Mn sites, which significantly enhanced the redox capacity and oxygen activation ability, thus improving the low-temperature catalytic combustion of chlorobenzene. Besides, the Ru-O-Mn sites boosted the transformation of chlorine-containing intermediate species to low-pollution species and accelerated the removal of Cl and the formation of CO₂, thus enhancing the chlorine tolerance of mullite catalysts. This study deepened the understanding of the catalytic combustion mechanism and provided a feasible strategy for the development of high-efficiency and chlorine-resistant catalysts for the catalytic combustion of CVOCs.