Structure Evolution and Associated Catalytic Properties of PtSn Bimetallic Nanoparticles

Bimetallic nanoparticles (NPs) often show new catalytic properties that are different from those of the parent metals. Carefully exploring the structures of bimetallic NPs is a prerequisite for understanding the structure-associated properties. Herein, binary PtSn NPs with tunable composition are prepared in a controllable manner. X-ray characterizations reveal that their structures evolve from SnO2-x -patched PtSn alloys to SnO2-x -patched Pt clusters when more tin is incorporated. An obvious composition-dependent catalytic performance is observed for the hydrogenation of α,β-unsaturated aldehydes: the selectivity to unsaturated alcohol increases substantially at high tin content, whereas the reaction rate follows a volcano shape. Furthermore, Pt sites are responsible for hydrogen dissociation, whereas oxygen vacancy (Ovac ) sites, provided by SnO2-x , drastically enhance the adsorption of carbonyl group.