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 Al2O3, 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 H2‐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 Pt3Sn 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 molC3H6 molPt−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.