Subnanometric Pt‐Sn Monolayers Over a Rod‐Shaped Al2O3 for Propane Dehydrogenation

Abstract Atomic layer deposition was applied to precisely disperse Pt on Sn‐, K‐modified Al 2 O 3 , while the dispersion of Pt depended strongly on the atmosphere. Pt presented as single‐atoms in oxidative atmosphere but both single‐atoms and clusters under reductive gas. After H 2 ‐treatment at 873 K, Pt single‐atoms, clusters and particles co‐existed in the catalysts, but their population varied considerably. The typical nanoparticles featured by crystallized Pt 3 Sn alloys, while the subnanometric clusters contained amorphous Pt−Sn alloys in a monolayer geometry. When tested for propane dehydrogenation at 873 K, the monolayers displayed outstanding performance; the mass specific activity approached 5.1 mol C3H6 mol Pt −1 s −1 , which was 2.7 times greater than that of particles. Structural analysis revealed that the amorphous Pt−Sn monolayer exposed more surficial Pt atoms surrounded by Sn atoms, which finely tuned the electronic property of Pt and thus favored the activation of C−H bond in propane.