Abstract: Gasoline soot particles pose a severe threat to the ecological environment and human health, and catalytic gasoline particulate filter (cGPF) is an effective purification technology, whose core component is a catalyst coating. In this study, MnO_x/CeO₂-ZrO₂ composite oxides were synthesized using different methods, and their soot oxidation performance was evaluated under low O₂ concentrations to develop catalyst coatings with excellent activity, stability, and water resistance. Herein, MnO_x/CeO₂-ZrO₂ prepared by impregnation (MCZ-IM) exhibits a T₅₀ (temperature required for 50% soot conversion) of 329 ℃ in 1% O₂ and 370 ℃ in 0.5% O₂, displaying better comprehensive performance compared to catalysts prepared by high-energy ball milling (MCZ-HB) and co-precipitation (MCZ-CP). Structure-activity relationship reveals that soot oxidation under low O₂ concentrations is weakly correlated with textural and structural properties, but strongly depends on the generation and migration of active oxygen species (AOS), especially superoxide (O₂^-) and peroxide (O₂^2-) anions, which are linked to redox properties, oxygen storage and release capacity, and amount of oxygen vacancies. The impregnation method more effectively enhances oxygen species adsorption, activation, and desorption, making it a more effective approach to enhancing AOS generation and mobility. This study not only provides a preparation strategy for particulate matter (PM) oxidation catalysts applicable to actual operating conditions, but also offers insights into the migration of AOS at low O₂ concentrations.

Key words: MnO_x/CeO₂-ZrO₂ catalyst, preparation method, soot, active oxygen species