Improving the catalytic selectivity of Pd catalysts is of key importance for various industrial processes and remains a challenge so far. Given the unique properties of single-atom catalysts, isolating contiguous Pd atoms into a single-Pd site with another metal to form intermetallic structures is an effective way to endow Pd with high catalytic selectivity and to stabilize the single site with the intermetallic structures. Based on density functional theory modeling, we demonstrate that the (110) surface of Pm3̅m PdIn with single-atom Pd sites shows high selectivity for semihydrogenation of acetylene, whereas the (111) surface of P4/mmm Pd₃In with Pd trimer sites shows low selectivity. This idea has been further validated by experimental results that intermetallic PdIn nanocrystals mainly exposing the (110) surface exhibit much higher selectivity for acetylene hydrogenation than Pd₃In nanocrystals mainly exposing the (111) surface (92% vs 21% ethylene selectivity at 90 °C). This work provides insight for rational design of bimetallic metal catalysts with specific catalytic properties.

中文翻译：

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金属间纳米结构中的孤立单原子钯位点：炔烃半加氢的高催化选择性

对于各种工业过程而言，提高Pd催化剂的催化选择性是至关重要的，并且迄今为止仍然是一个挑战。鉴于单原子催化剂的独特性能，将相邻的Pd原子与另一种金属隔离成一个Pd位点以形成金属间结构是赋予Pd具有高催化选择性并稳定具有金属间结构的单个位点的有效方法。基于密度泛函理论建模，我们证明的（110）表面PM 3米PDIN具有单原子钯位点显示出高的选择性乙炔半氢化，而的（111）面P 4 / MMM的Pd ₃在Pd中，三聚体位点显示出低选择性。通过实验结果进一步证实了这一想法，主要暴露于（110）表面的金属间化合物PdIn纳米晶体比主要暴露于（111）表面的Pd ₃ In纳米晶体对乙炔氢化的选择性高得多（在90°C下乙烯的选择性为92％vs 21％） C）。这项工作为合理设计具有特定催化性能的双金属金属催化剂提供了见识。