CaO-Promoted Lattice Oxygen Activation and Antichlorine Poisoning over Mullite for Catalytic Chlorobenzene Combustion

The degradation of chlorine-containing volatile organic compounds (Cl–VOCs) utilizing catalytic combustion technology is subject to the paradox of toxic byproduct formation and catalyst chlorine poisoning. Herein, a CaO-assisted strategy is proposed to resolve the awkward stuff for improving the catalytic combustion performance of chlorobenzene on SmMn2O5. The CaO-collaborated SmMn2O5 exhibits a significant decrease in T90 by 142 and 125 °C compared with unmodified and inert SiO2-composited SmMn2O5, respectively. The integrated characterization results confirm that CaO collaboration causes electron transfer from CaO to SmMn2O5, resulting in a reduction of the orbital overlap between Mn and O atoms to activate lattice oxygen (Olatt). The activated Olatt enables chlorobenzene to combust completely at a lower temperature of 275 °C at which toxic byproducts are not generated. Furthermore, the switching of the dechlorination site from SmMn2O5 to CaO avoids chlorine poisoning of active sites on SmMn2O5 and thus endows CaO-collaborated SmMn2O5 with prominent stability.