The combination of two or more metals, forming alloys, core–shells, or other complex heterometallic nanostructures, has substantially spanned the available options to finely tune electronic and structural properties, opening a myriad of opportunities that has yet to be fully explored in different fields. In catalysis, the rational exploitation and design of bimetallic and trimetallic catalysts has just started. Several major aspects such as stability, phase segregation, and alloy–dealloy mechanisms have yet to be deeply understood and correlated with intrinsic factors such as nanoparticle size, composition, and structure and with extrinsic factors, or external agents, such as temperature, reaction gases, and support. Here, by combining model catalysts based on AuCu nanoparticles supported on silica or alumina with in situ characterization techniques under redox pretreatments and CO oxidation reaction, we demonstrate the crucial role of the support with regard to determining the stable active phase of bimetallic supported catalysts. This strategy, associated with theoretical studies, could lead to the rational design of unique active sites.

中文翻译：

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载体在双金属纳米颗粒转化和催化性能中的关键作用

两种或多种金属，形成合金，核-壳或其他复杂的异金属纳米结构的组合，已经大大扩展了可用的选项，以微调电子和结构特性，从而开辟了许多在不同领域中尚待充分探索的机会。在催化方面，双金属和三金属催化剂的合理开发和设计才刚刚开始。稳定性，相偏析和合金-合金机制等几个主要方面尚未深入理解，并且与内在因素（例如纳米粒子大小，组成和结构）以及外在因素或外部因素（例如温度，反应气体）相关联，以及支持。这里，通过将基于负载在二氧化硅或氧化铝上的AuCu纳米颗粒的模型催化剂与氧化还原预处理和CO氧化反应下的原位表征技术相结合，我们证明了载体在确定双金属负载的催化剂的稳定活性相方面的关键作用。这种与理论研究相关的策略可能会导致合理设计独特的活动场所。