Atomic‐level confinement of PtCu nanoclusters within MFI‐type zeolite enables unprecedented kinetics in alkyne semi‐hydrogenation

Abstract The selective semi‐hydrogenation of phenylacetylene (PA) to styrene (ST) represents a critical industrial reaction, essential for producing polymer‐grade styrene. Yet, achieving high selectivity at high conversions remains fundamentally challenging due to competing over‐hydrogenation. Here we report an atomic‐scale approach for encapsulating ultrafine PtCu (Platinum, Copper) bimetallic nanoclusters (NCs) within the microporous TS‐1 zeolite matrix through a ligand‐assisted hydrothermal strategy. Remarkably, the as‐synthesized PtCu@TS‐1 catalyst exhibited an unprecedented turnover frequency (TOF) of 2006.7 h −1 and a superior styrene yield of 87.7%, significantly surpassing conventional Pt‐based catalysts. Advanced characterization and in situ spectroscopy revealed that electron‐rich Pt sites, induced by electron transfer from Cu in confined PtCu ensembles, substantially lower the activation barrier for hydrogen dissociation, accelerating selective hydrogenation. Moreover, the atomic confinement effect within the zeolite structure effectively modulates intermediate adsorption and accelerates product desorption, thus overcoming the selectivity‐activity trade‐off. This study introduces a generalizable atomic‐level catalyst design principle, highlighting the immense potential of quantum‐sized bimetallic clusters within porous materials for precisely tuning reaction selectivity and activity.