Tri‐Atomic Palladium‐Supported Catalysts: A Strategy to Enhance Selective Acetylene Hydrogenation Performance

ABSTRACT Atomically precise supported nanocluster catalysts (APSNCs), distinguished by their well‐defined structure, controlled composition, and presence of metal–metal bond, exhibit unique catalytic performance and provide an ideal platform for investigating structure‐performance relationships at the atomic level. However, the synthesis of stable APSNCs remains a great challenge, mainly due to their limited dispersibility and strong tendency to aggregate during the synthesis process. Herein, we report the synthesis of a tri‐atomic Pd catalyst supported on carbon nanotubes (Pd 3 /CNT) achieved through a precursor engineering strategy. X‐ray absorption spectroscopy (XAS) and density functional theory (DFT) calculations confirm a planar triangular Pd 3 configuration. This unique configuration endows Pd 3 /CNT with exceptional catalytic activity, achieving 100% acetylene conversion with 90.0% ethylene selectivity at 80°C, outperforming both Pd 1 /CNT (conversion of 27.2%, selectivity of 94.6% at 80°C) and Pd/C (conversion of 100%, negative selectivity of −118.9% at 39°C). In situ infrared spectroscopy and DFT analysis reveal that the tri‐atomic Pd sites can simultaneously promote the di‐σ type adsorption of acetylene and the rapid dissociation of H 2 into H * , while weakening the π ‐type adsorption of ethylene, thus enabling efficient co‐activation at relatively low temperature. These findings highlight the critical role of tailoring for atomic‐scale nanoclusters in enabling high‐efficiency catalytic processes.