The bimetallic Pt-Sn catalysts are known to be the most efficient ones for propane dehydrogenation reaction; however, the synthesis of bimetallic Pt-Sn nanocluster (below 1 nm) with an alloy structure still remains a formidable challenge. An approach for the controllable synthesis of Pt-Sn nanocluster based on Surface Organometallic Chemistry on oxide concept is developed here, which involves two basic steps: the sequential grafting of Pt(COD)Me-2 and HSnPh3 at the surface of dehydroxylated theta-Al2O leading to the formation of well-defined bimetallic surface compound consisting of [( AlO-)Pt(COD)Me] and [(=AlO-)SnPh3] fragments, and the hydrogenolysis of this surface compound under a mild condition giving rise to the ultra-small bimetallic Pt-Sn cluster around 0.75 nm. The achieved Pt-Sn/theta-Al2O3 catalysts exhibit high activity, selectivity and stability in propane dehydrogenation to propylene. (C) 2019 Elsevier Inc. All rights reserved.