The fabrication of ultrathin alloy shells as heterogeneous catalysts to increase the utilization efficiency and enhance the catalytic activity of metal atoms has been recognized as an effective method for the construction of efficient metal nanocatalysts, particularly noble-metal nanocatalysts. In this study, we demonstrate the successful formation of Pd-M (M = Ni, Ag, Cu) alloy shells with a tunable thickness on preformed nanoscale Pd seeds. The success of this synthesis mainly relies on the combination of the slow reduction of “M” ions and the subsequent diffusion of M ad-atoms into the surface lattice of Pd seeds. The composition of the Pd-M alloy shell is easily tuned by changing the type and amount of the added precursor, and the shell thickness is manipulated according to the reaction time. More significantly, the surface structure of these alloy shells is maintained after the reaction, implying that any desired surface structure of Pd-M alloy shells can be prepared by using the appropriate starting materials. Further catalytic evaluation of the hydrogenation of chloronitrobenzenes shows that these alloy surfaces exhibit significantly improved selectivity compared to the Pd seeds. The Pd-Ni alloy surfaces exhibit much better catalytic selectivity (as high as > 99%) than Pd catalysts.

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作为增加催化剂的利用效率并增强金属原子的催化活性的超薄合金壳作为非均相催化剂的制备已经被认为是构建有效的金属纳米催化剂，特别是贵金属纳米催化剂的有效方法。在这项研究中，我们证明了在预先形成的纳米级Pd种子上成功形成了厚度可调的Pd-M（M = Ni，Ag，Cu）合金壳。该合成的成功主要取决于“ M”离子的缓慢还原和随后的M ad原子扩散到Pd种子的表面晶格中的组合。通过改变添加的前驱体的类型和数量，可以轻松地调节Pd-M合金壳的成分，并根据反应时间控制壳的厚度。更重要的是 这些合金壳的表面结构在反应后得以保持，这意味着可以通过使用适当的起始原料来制备任何所需的Pd-M合金壳的表面结构。氯硝基苯氢化的进一步催化评估表明，与Pd晶种相比，这些合金表面表现出显着改善的选择性。Pd-Ni合金表面显示出比Pd催化剂更好的催化选择性（高达99％以上）。

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