Hydrogen Bond Network Induced by Surface Ligands Shifts the Semi-hydrogenation Selectivity over Palladium Catalysts

Abstract

Tuning the metal–ligand interfaces of heterogeneous catalysts has emerged as an effective strategy to optimize their catalytic performance. However, improving the selectivity via organic modification remains a challenge so far. In this work, we demonstrate a simple ligand modification by preparing cysteamine-coated ultrathin palladium nanosheets. The as-prepared catalyst exhibits excellent selectivity with durability during catalytic hydrogenation of terminal alkynes, superior to most previously reported ligand-protected palladium catalysts. Further study reveals that a zwitterionic transformation occurs on the palladium interface under the H2 conditions, generating a rigid hydrogen bond network. Such an unexpected effect beyond the traditional steric effect derived from van der Waals interactions makes the catalytic surface favor the hydrogenation of alkynes over alkenes without significantly sacrificing the catalytic activity. These results not only provide a unique steric effect concept for surface coordination chemistry but also provide a practical application to improve the selectivity and activity comprehensively.

Frustrated Lewis pairs on pentacoordinated Al3+-enriched Al2O3 promote heterolytic hydrogen activation and hydrogenation

“…DFT calculation was further applied to understand the hydrogenation process. 53–55 The structure of γ-Al 2 O 3 was constructed following the same method in our previous study. 56 The d-Al 2 O 3 model with surface Al p was constructed from γ-Al 2 O 3 following a dehydration process.…”

Ligand‐Mediated Magnetism‐Conversion Nanoprobes for Activatable Ultra‐High Field Magnetic Resonance Imaging

“…In contrast, for À S À groups, at neutral pH, the À S À ligand engages in weak hydrogen bonds with water molecules (S•••HÀ O bonds), resulting in a short τ' m . In contrast, under acidic pH conditions, the -SH ligand promotes the formation of robust hydrogen bonds with water molecules (SÀ H•••O bonds), [12] thereby extending τ' m and expediting the T1 relaxation.…”

Unraveling Hydrogenation Kinetic Behavior of Transition Metal Oxides via Decoupling Dihydrogen Dissociation and Substrate Activation

“…The semihydrogenation of alkynes to alkenes is widely used in the industrial production of polymers and pharmaceutical intermediates. − Transition metal oxide (e.g., TiO 2 , CeO 2 , and ZrO 2 )-supported noble metals (e.g., Pd and Pt) are conventional catalysts applied in the semihydrogenation of alkynes, in which both noble metal sites and oxide support have been identified as active sites. Specifically, Pd and Pt species can efficiently activate hydrogen, but undesired overhydrogenation products are commonly attained because alkenes are not easily desorbed on the noble metal ensembles.…”