Controlled Strong Metal–Support Interactions in Pt@GaO x Catalysts for Efficient and Durable Propane Dehydrogenation

Abstract

Pt-based catalysts are widely used for propane dehydrogenation (PDH), yet high-temperature operation causes severe deactivation through sintering and coking. Strong metal–support interaction (SMSI) offers a potential solution by improving durability via oxide encapsulation, although excessive or uncontrolled encapsulation often reduces activity by blocking accessible metal sites. These limitations make it a key outstanding challenge to achieve precisely controlled SMSI overlayer thickness and to clarify its role in balancing activity and stability. Here, we addressed this issue by regulating Ga loading on SiO2 through atomic layer deposition and leveraging the high mobility of GaOx during reduction together with strong Pt–Ga interactions. This strategy enabled atomic-scale control of GaOx encapsulation and revealed a clear thickness–performance relationship, with near-monolayer Pt@GaOx outperforming bilayer and 3–4-layer structures for PDH. The optimized catalyst delivered a propylene formation rate of 160 molC3H6·gPt–1·h–1 with >97% selectivity and stable operation for 260 h. Spectroscopic and kinetic studies showed that Pt-induced interfacial charge redistribution tuned defect-rich, coordinatively unsaturated Ga sites, enabling C–H activation and propylene desorption, thereby limiting deep dehydrogenation and coke formation. In parallel, geometric confinement by the GaOx overlayer inhibited sintering. These findings establish controlled SMSI as an effective strategy for engineering oxide–metal interfaces toward active and durable catalysis.