Abstract 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 °C 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.

中文翻译：

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增加铈含量对Rh/二氧化铈-氧化锆三元催化剂活性和水热稳定性的可能负面影响

摘要 本文研究了用于汽油车排放控制的 Rh/CexZr1-xO2 (x = 0, 0.05, 0.3, 0.5) 模型三元催化剂的活性和水热稳定性。在具有不同 Ce/Zr 比的 Rh/CexZr1-xO2 样品中，Rh/ZrO2 样品比其余样品表现出明显更好的活性和水热稳定性。在 Rh/CexZr1-xO2 催化剂中含有更多的 Ce 组分的影响与强的 Rh-O-Ce 相互作用有关，这往往会使铑物种过度稳定。在 1050 °C 和 10% H2O 空气中水热老化 12 小时后，可在大部分载体氧化物中发现大量此类铑原子。不同的是，铑在 Rh/ZrO2 催化剂表面的烧结是催化剂在水热老化过程中失活的主要原因。