Gold in Three-way Catalysis

在本项目含金三元催化剂的第一阶段，发现双金属钯金体系的催化行为对载体的性质有很大的依赖性。当负载在la掺杂的氧化铝上时，金对Pd成分起毒害作用，甚至增强Pd在高温下释放氧化亚氮的不利性质。当CeZrO2负载时，Pd和Au的性质结合良好，因此在满足热稳定性要求的情况下，含Au三元催化剂可能成为现实。该项目旨在通过相关材料的结构表征（例如XPS， XAFS， LEIS, HAADF-STEM）来阐明这些差异的来源，同时也通过对不同组成的模型废气进行XAFS研究，研究热应力后双金属催化剂的催化行为及其结构原因，并在必要时确定催化剂在高温下的稳定策略。

In the first stage of the present project on Au-containing three-way catalysts, a drastic dependence of the catalytic behavior of bimetallic Pd-Au systems on the nature of the support was found. When supported on La-doped alumina, gold acts as a poison with respect to the Pd component and even enhances the adverse property of Pd to release nitrous oxide at elevated temperatures. When supported on CeZrO2, properties of Pd and Au combine favorably, so that Au-containing three-way catalysts may become a reality provided that thermal stability requirements can be fulfilled. The project aims at elucidating the origin of these differences by structural characterization of relevant materials (e.g. by XPS, XAFS, LEIS, HAADF-STEM), but also by operando XAFS studies in model exhausts of different composition, at investigating the catalytic behavior of the bimetallic catalysts after thermal stress and its structural reasons, and if necessary at identifying strategies for stabilization of the catalysts under high temperatures.