Syntheses of water-soluble octahedral, truncated octahedral, and cubic Pt-Ni nanocrystals and their structure-activity study in model hydrogenation reactions.

We developed a facile strategy to synthesize a series of water-soluble Pt, Pt(x)Ni(1-x) (0 < x < 1), and Ni nanocrystals. The octahedral, truncated octahedral, and cubic shapes were uniformly controlled by varying crystal growth inhibition agents such as benzoic acid, aniline, and carbon monoxide. The compositions of the Pt(x)Ni(1-x) nanocrystals were effectively controlled by choice of ratios between the Pt and Ni precursors. In a preliminary study to probe their structure-activity dependence, we found that the shapes, compositions, and capping agents strongly influence the catalyst performances in three model heterogeneous hydrogenation reactions.