Redox-Acidity Interplay in Eu-Promoted PtSn₂ Catalysts for Selective and Stable Propane Dehydrogenation

Heterogeneous catalysts based on Pt alloys are widely employed in propane dehydrogenation (PDH), yet challenges such as coking and poor nanoparticle stability hinder their broader industrial deployment. Strategies to enhance dispersion and tune the catalyst surface properties remain at the forefront of catalyst design. Here, we demonstrate a new class of PtSn₂-based catalysts promoted by rare-earth elements for efficient and stable PDH. Among the rare-earth screened, europium (Eu) delivers the most pronounced promotional effect, enabling the formation of ∼1.3 nm PtSn₂ nanoparticles with improved thermal stability. Through its redox flexibility (Eu³⁺/Eu²⁺), Eu modulates the electronic environment of Pt, tunes surface acidity, and suppresses coke accumulation by directing carbon species away from active sites and onto the support. This work shows that rare-earth elements can serve as multifunctional promoters in alloy catalysts, influencing both structural dispersion and catalytic surface chemistry. The optimized catalyst (0.5% Pt-3% Sn-2% Eu on γ-Al₂O₃) achieves a 40.6% propylene yield at 575 °C and a low deactivation rate (0.047 h^-1), under conditions relevant to industrial practice. Our findings offer a new strategy for designing high-performance diluted alloy catalysts through rare-earth promotion, applicable to other dehydrogenation and hydrocarbon upgrading reactions where coke suppression and acid-base balance are critical.