Stereoselective production of alkenes from the alkyne hydrogenation plays a crucial role in the chemical industry. However, for heterogeneous metal catalysts, the olefins in cis-configuration are usually dominant in the products due to the most important and common Horiuti–Polanyi mechanism involved over the metal surface. In this work, through combined theoretical and experimental investigations, we demonstrate a novel isomerization mechanism mediated by the frustrated hydrogen atoms via the H₂ dissociation at the defect on solid surface, which can lead to the switch in selectivity from the cis-configuration to trans-configuration without overhydrogenation. The defective Rh₂S₃ with exposing facet of (110) exhibits outstanding performance as a heterogeneous metal catalyst for stereoselective production of trans-olefins. With the frustrated hydrogen atoms at spatially separated high-valence Rh sites, the isolated hydrogen mediated cis-to-trans isomerization of olefins can be effectively conducted and the overhydrogenation can be completely inhibited. Furthermore, the bifunctional Rh–S/Pd nanosheets have been synthesized through the surface modification of Pd nanosheets with rhodium and sulfide. With the selective semihydrogenation of alkynes into cis-olefins catalyzed by the small surface PdS_x ensembles, the bifunctional Rh–S/Pd nanosheets exhibit excellent activity and stereoselectivity in the one-pot alkyne hydrogenation into trans-olefin, which surpasses the most reported homogeneous and heterogeneous catalysts.

中文翻译：

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受阻氢原子介导的炔烃立体选择性氢化反应生成反式烯烃的异构化反应

从炔烃氢化中立体选择性地生产烯烃在化学工业中起着至关重要的作用。然而，对于非均相金属催化剂，由于涉及金属表面的最重要和最常见的 Horiuti-Polanyi 机制，顺式构型的烯烃通常在产物中占主导地位。在这项工作中，通过理论和实验相结合的研究，我们展示了一种新的异构化机制，由受阻氢原子通过固体表面缺陷处的H ₂解离介导，这可以导致选择性从顺式构型转变为反式构型。-没有过度氢化的构型。有缺陷的 Rh ₂ S ₃(110) 的暴露面作为用于立体选择性生产反式烯烃的多相金属催化剂表现出优异的性能。与空间分离的高化合价的Rh位点沮丧的氢原子，所述分离的氢介导顺式-到-反式烯烃的异构能够有效地进行，并且过度氢化可完全抑制。此外，通过用铑和硫化物对 Pd 纳米片进行表面改性，合成了双功能 Rh-S/Pd 纳米片。通过小表面 PdS _x催化炔烃选择性半氢化成顺式烯烃整体而言，双功能 Rh-S/Pd 纳米片在一锅炔烃氢化成反式烯烃中表现出优异的活性和立体选择性，超过了报道最多的均相和多相催化剂。