Possible negative influences of increasing content of cerium on activity and hydrothermal stability of Rh/ceria-zirconia three-way catalysts☆

• 作者: Tianming Huang Meiqing Shen Guanghao Cheng Yunhao Wang Jianqiang Wang Wei Li Se H.Oh Gongshin Qi Ming Yang Jun Wang
• 来源期刊: 稀土学报（英文版）
• 年，卷（期）: 2021,（7）
• 所属期刊栏目: RARE EARTH CATALYSIS
• 页码范围: 797-804
• 页数: 8页
• 语种: 英文

摘要

The activity and hydrothermal stability of the Rh/CexZr1-xO2 (x = 0, 0.05, 0.3, 0.5) model three-way catalysts for gasoline vehicle emissions control were investigated in this work. Among the Rh/CexZr1-xO2 samples with different Ce/Zr ratios, the Rh/ZrO2 sample exhibits a significantly better activity and hydrothermal stability than the rest of the samples. The impacts of having more Ce components in the Rh/CexZr1-xO2 catalysts are associated with the strong Rh-O-Ce interaction that tends to over stabilize the rhodium species. A significant amount of such rhodium atoms can be found in the bulk of the support oxides after a hydrothermal aging at 1050 ℃ with 10％ H2O in air for 12 h. Differently, the sintering of rhodium on the surface of Rh/ZrO2 catalysts is the main reason for the catalyst deactivation during the hydrothermal aging. These findings provide an example where high dispersion of supported metal induced by strong metal-support interactions does not necessarily lead to high catalytic activity.