摘要
Gasoline soot particles pose a severe threat to the ecological environment and human health,but they can be potentially filtered out by using catalytic gasoline particulate filter(cGPF),whose core component is a catalyst coating.To develop more effective catalyst coatings with excellent activity,stability,and water resistance,a kind of composite oxide MnO_(x)/CeO_(2)-ZrO_(2) was synthesized using different methods,and its soot oxidation performance was evaluated under low O_(2) concentrations.Herein,MnO_(x)/CeO_(2)-ZrO_(2) prepared by impregnation(abbreviated as MCZ-IM)exhibits a T_(50)(temperature required for 50% soot conversion)of 329℃in 1%O_(2) and 370℃ in 0.5%O_(2),displaying better comprehensive performance when compared to catalysts prepared by high-energy ball milling(abbreviated as MCZ-HB)and co-precipitation(abbreviated as MCZ-CP).Structure-activity relationship reveals that soot oxidation under low O_(2) concentrations is weakly correlated with textural and structural properties,but strongly depends on the generation and migration of active oxygen species(AOS),especially superoxide(O_(2)^(-))and peroxide(O_(2)^(2-))anions,which are linked to redox properties,oxygen storage and release capacity,as well as amount of oxygen vacancies.The impregnation method enhances oxygen species adsorption,activation and desorption more effectively,endowing it with a more effective approach to enhancing AOS generation and mobility.Therefore,this study not only provides a preparation strategy for particulate matter oxidation catalysts applicable to actual operating conditions,but also offers insights into the migration of AOS at low O_(2) concentrations.
汽油机尾气碳烟颗粒严重威胁着生态环境和人类健康,而催化型汽油颗粒物过滤器(cGPF)是一种有效的净化技术,其核心为催化剂涂层。本研究采用不同制备方法构筑了MnO_(x)/CeO_(2)-ZrO_(2)复合氧化物,在低O_(2)浓度下考察了其碳烟氧化性能,旨在开发具有卓越催化活性、稳定性以及抗水性的碳烟氧化催化剂涂层。结果表明,通过浸渍法制备的MnO_(x)/CeO_(2)-ZrO_(2)(MCZ-IM)在1%O_(2)中,其T_(50)(碳烟转化率达50%所需的温度)为329℃;在0.5%O_(2)中,其T_(50)为370℃。相较于高能球磨法(MCZ-HB)和共沉淀法(MCZ-CP)制备的催化剂,MCZ-IM展现出更优的综合性能。构效关系表明,低O_(2)浓度下碳烟氧化性能与催化剂的织构和结构性质呈弱相关,而与活性氧物种(AOS)——超氧(O_(2)^(-))和过氧(O22-)阴离子的生成及迁移密切相关,其中涉及氧化还原性能、储释氧能力以及氧空位数量。MCZ-IM在氧物种的吸附、活化和脱附方面更具优势,因此浸渍法被认为是提高AOS生成和迁移的更优方法。本研究不仅提供了一种适用于实际运行条件下颗粒物(PM)氧化催化剂的制备策略,而且深入揭示了低O_(2)浓度环境中AOS的迁移机制。
出处
《无机材料学报》
北大核心
2025年第11期1300-1308,I0024-I0026,共12页
Journal of Inorganic Materials
基金
Advanced Materials-National Science and Technology Major Project(2024ZD0606500)
National Natural Science Foundation of China(21902110)
Sichuan Provincial Science Foundation(2023NSFSC0093)。
