Tailoring Oxygen Activation Sites and Surface Acidity on MnO ₂ via Mo Doping and CeO ₂ Modification for Toluene Oxidation under Coexisting Chlorobenzene and SO ₂

Enhancing the activity and stability of non-noble-metal-based catalysts is of great significance for the catalytic oxidation of VOCs containing sulfur and chlorine. This work constructed a Ce0.20Mo0.4MnO2 catalyst with spatial isolation effect by means of ion doping and surface modification. The introduction of Mo significantly reduced the oxygen vacancy formation energy, thereby promoting the adsorption and activation of oxygen. Moreover, CeO2 modification enhances the surface acidity of the catalyst and effectively mitigated the poisoning effects of sulfur and chlorine containing acidic oxides. As a result, the optimized Ce0.20Mo0.4MnO2 catalyst maintained excellent activity, achieving over 99% toluene conversion for 1000 h (250 °C, WHSV = 36 000 mL g–1 h–1). Theoretical calculations further confirmed that this catalyst of Ce0.20Mo0.4MnO2 exhibited the lowest reaction energy barrier and oxygen dissociation energy. This study offers a promising strategy for designing S/Cl-resistant and durable catalysts for the efficient oxidation of complex VOC mixtures under realistic industrial conditions.