Some special structural models of NCs, such as core–shell, 7,8 onion-like, 9 quasi-janus structures 10 and crown-jewel (CJ) structures 11,12 have been found to have structure-dependent properties and are an important focus of nanostructure research. 5,6 With regard to electrocatalysis, much effort has been dedicated to improving the catalytic performance of nanoalloys by designing different kinds of structures. 3,4 By tuning their size, structures, and chemical compositions as well as the surface state properties, the unique properties of bimetallic NCs can be utilized in a large range of fields, especially in heterogeneous catalysis. 1,2 Bimetallic nanoclusters exhibit enhanced and more complex properties than the corresponding monometallic components attributed to the synergistic effect of the different elements. Introduction Metallic nanoclusters (NCs) have received great attention in materials science and engineering for their excellent properties owing to their small size and large surface-volume ratio. The melting point increases as cluster size increases, which agrees well with Pawlow's law. Furthermore, the effects of size and morphology on melting properties are discussed. Besides, Cubo–Ico transformation is size-dependent and only found in small clusters. More importantly, we found that CJ-structured PdCu clusters undergo a structural transformation from cuboctahedral (Cubo) to icosahedral (Ico) structure by heating or after the adsorption of reaction intermediate, which indicates that Cubo is less stable than the Ico structure. In addition, MD simulation results confirm the thermal stability of CJ-structured PdCu. Additionally, we attempt to explain the high catalytic activity of PdCu SAAs by electronic structure analysis. The DFT results reveal that CJ-structured PdCu SAAs show excellent HER and ORR catalytic performance, and can be regarded as a promising alternative to Pt catalysts towards the ORR or HER. In this work, the catalytic properties and thermal stability of PdCu SAAs with a crown-jewel (CJ) structure are studied by density functional theory (DFT) calculations and the molecular dynamics (MD) simulation method. Single-atom alloys (SAAs) have been emerging as an important field of research in electrocatalysis owing to extremely high atom utilization, unique structure and high catalytic activity.
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