Abstract As is well known, impregnation of precursors of Ce and Zr onto as-prepared Al2O3 powders is a commonly used approach to prepare CeO2-ZrO2/Al2O3 composite. In this work, a highly thermal stable CeO2-ZrO2/Al2O3 composite was synthesized by modifying the conventional preparation procedure, i.e., the precursor of Al2O3 thermal treated at comparatively lower temperature (200 °C) was applied to conduct the impregnation process. The characterization results of the supported Pd-only three-way catalysts reveal that in the modified sample, stronger interaction between CeO2-ZrO2 and Al2O3 is achieved, which consequently gives rise to higher thermal stability of the catalyst. Upon hydrothermal aging treatment, only slight aggregation of the CeO2-ZrO2 and Al2O3 particles takes place, meanwhile phase transformation of γ-Al2O3 and phase separation of CeO2-ZrO2 component are successfully suppressed. As a consequence, Pd species supported on the modified CeO2-ZrO2/Al2O3 composite remain finely dispersed, and more oxidative PdO species are maintained owing to the intimate interaction between Pd and CeO2-ZrO2. Therefore, improved reduction capability and superior three-way catalytic performance are achieved for the modified Pd/CeO2-ZrO2/Al2O3 catalyst after aging treatment.

中文翻译：

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高热稳定性的CeO 2 -ZrO 2 /Al 2 O 3 复合材料的优化合成用于改进的仅Pd三元催化剂

摘要 众所周知，将 Ce 和 Zr 的前驱体浸渍到所制备的 Al2O3 粉末上是制备 CeO2-ZrO2/Al2O3 复合材料的常用方法。在这项工作中，通过改进常规制备程序，即应用在较低温度（200℃）下热处理的 Al2O3 前驱体进行浸渍过程，合成了高度热稳定的 CeO2-ZrO2/Al2O3 复合材料。负载型 Pd 三元催化剂的表征结果表明，在改性样品中，CeO2-ZrO2 和 Al2O3 之间实现了更强的相互作用，从而提高了催化剂的热稳定性。水热时效处理后，CeO2-ZrO2 和 Al2O3 颗粒仅发生轻微聚集，同时成功抑制了γ-Al2O3 的相变和CeO2-ZrO2 组分的相分离。因此，负载在改性 CeO2-ZrO2/Al2O3 复合材料上的 Pd 物种保持精细分散，并且由于 Pd 和 CeO2-ZrO2 之间的密切相互作用，保持了更多的氧化 PdO 物种。因此，经过老化处理的改性 Pd/CeO2-ZrO2/Al2O3 催化剂实现了更高的还原能力和优异的三元催化性能。