4.7 Article

Rh Nanoparticles Dispersed on ZrO2-CeO2 Migrate to Al2O3 Supports to Mitigate Thermal Deactivation via Encapsulation

期刊

ACS APPLIED NANO MATERIALS
卷 6, 期 11, 页码 9805-9815

出版社

AMER CHEMICAL SOC
DOI: 10.1021/acsanm.3c01535

关键词

three-way catalyst; encapsulation; particlemigration; rhodium nanoparticle; ZrO2-CeO2

向作者/读者索取更多资源

This study investigates the performance of catalysts after real engine aging and finds that pre-aged catalysts can maintain better catalytic performance at high temperatures. It is found that the migration of Rh nanoparticles from the ZC surface to the Al2O3 binder interface plays a crucial role in mitigating the encapsulation of Rh nanoparticles by ZC. By using a dual-oxide support formulation, the deterioration extent of the catalyst and the oxygen storage capacity performance can be effectively improved.
Full-scale monolithic three-way catalysts (TWCs) comprisingRh,oxygen-scavenging ZrO2-CeO2 (ZC), and gamma-Al2O3 as a binder component were studiedafter real engine aging. The fatal irreversible deactivation thatoccurred under stoichiometric-lean-rich perturbation at 1000 degrees Cfor 40 h (SLR aging) was attributed to the complete encapsulationof Rh nanoparticles by ZC, leading to the physical blockage of gasadsorption. Preaging the catalyst under a rich condition at 1000 degrees Cfor 40 h (R aging) drastically mitigated this deactivation, i.e.,the catalyst with R-SLR combined aging sustained its catalyticperformance much better than the catalyst with SLR aging at the sametemperature (1000 degrees C) and total time (80 h). X-ray mapping andhigh-temperature environmental electron microscopic analyses suggestedthat R aging promoted the migration of Rh nanoparticles across theZC surface toward the boundary with the Al2O3 binder. Owing to the strong bonding with the Al2O3 surface, Rh nanoparticles were trapped at or near the boundary.Consequently, these Rh nanoparticles were unlikely to be fully coveredby ZC even under the SLR aging condition because the encapsulationwas induced through repetitive oxygen release/storage cycles at theRh/ZC interface. Thus, we propose that Rh nanoparticles in contactwith ZC and Al2O3 played crucial roles to hinderthe encapsulation caused by SLR aging at 1000 degrees C. Rh nanoparticlessupported on the dual-oxide support of ZC and Al2O3 were subjected to engine aging and chassis dynamometer tests.The deterioration extents of the TWC and oxygen storage capacity performanceswere successfully mitigated using this dual-oxide support formulation.

作者

我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。

评论

主要评分

4.7
评分不足

次要评分

新颖性
-
重要性
-
科学严谨性
-
评价这篇论文

推荐

暂无数据
暂无数据