Synthesis and comparative electrocatalytic study of Pt₃Ni nanoctahedra and nanocubes

Shape-control synthesis of Pt-based catalysts is possibly one of the potential shortcuts to enhance the performance of catalysts used in the proton-exchange membrane fuel cells. Based on bulk material study, an insight is that different crystal facets may exhibit diverse catalytic activities and poison-resistant capabilities. To prove this concept in nano-scaled catalysts, a challenge is to prepare monodisperse polyhedral nanocatalyst not only in size but also in shape. In this presentation, we demonstrate a facile and robust synthetic approach for preparation of high-quality Pt₃Ni nanoctahedra and nanocubes. Our comparative study on these fuel cell electrocatalysts towards oxygen-reduction reaction (ORR) indicates that the ORR activity of {111}-bounded Pt₃Ni nanoctahedra is ∼5 folds higher than that of {100}-terminated nanocubes with a similar size. The specific and mass activities of these Pt₃Ni nanoctahedra loaded on carbon black are ∼7 and ∼4 times, respectively, higher than those of the state-of-the-art carbon supported Pt catalyst.