MnO <i> _x </i> /CeO ₂ -ZrO ₂ Composite Oxides: Construction and Application in Soot Oxidation

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, MnOx/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, MnOx/CeO2-ZrO2 prepared by impregnation (MCZ-IM) exhibits a T50 (temperature required for 50% soot conversion) of 329 in 1% O 2 and 370 in 0.5% O 2, 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.