Currently, manganese-based catalysts suffer from insufficient low-temperature activity and a tendency to chlorine poisoning-induced deactivation during the catalytic combustion of chlorobenzene. This study successfully developed Nb-Ca/MnO2 catalysts, with the Nb(2)-Ca(2)/MnO2 catalyst exhibiting superior performance: A T90 of 340°C for CB conversion at 15,000 mL·g⁻¹·h⁻¹, over 85% conversion retention during a 30-hour test, and a significant reduction in polychlorinated by-products. Catalyst characterization results indicated that Nb existed in the form of Nb2O5. A small amount of Nb substantially increased the Mn3⁺/Mn4⁺ ratio and markedly raised the proportion of surface adsorbed oxygen. Furthermore, Nb loading enhanced the low-temperature redox capability of the catalyst. The introduction of Nb significantly altered the distribution of acidic sites, promoted the desorption of chlorine species, and effectively suppressed the formation of polychlorinated by-products. In situ DRIFTS results revealed the generation of abundant bidentate carbonates and maleates during the reaction, along with a significant reduction in chlorine species on the spent catalyst. The Nb-Ca/MnO2 catalyst exhibited advantages in both catalytic activity and resistance to chlorine poisoning.
Wu et al. (Sat,) studied this question.