Nanoconfinement-engineered sintering-resistant Pt–high-entropy alloy clusters for dehydrogenation

Developing high-entropy alloy clusters (HEACs) with precise size-composition control and exceptional thermal stability faces persistent synthesis barriers, particularly in controlling Ostwald ripening and particle-migration-driven sintering during catalytic operation. Herein, we demonstrate a mechanochemistry-driven interfacial confinement strategy that enables the self-assembly of Pt-HEACs on MgO nanoarchitectures via dynamic adsorption between Mg(OH) 2 nanoparticles and M x (acac) y precursors. This process produces island-type Pt-HEACs/MgO heterostructures exhibiting exceptional anti-sintering properties, maintaining sub-3 nm dispersion on SiO 2 supports even after 800 ℃ H 2 treatment—a stark contrast to the severe aggregation observed in non-confined counterparts. When evaluated for propane dehydrogenation, the Pt-HEACs/MgO/SiO 2 achieves near-equilibrium propane conversion (45.9 %) and moderate catalyst life time (τ without H 2 ) 546.3 h. Operational spectra and DFT analysis reveal that higher configurational entropy in Pt-HEACs enhances electron enrichment at Pt active sites, which kinetically promotes propylene desorption and consequently suppresses carbon deposition.