Exposed facet-controlled N(2) electroreduction on distinct Pt(3)Fe nanostructures of nanocubes, nanorods and nanowires

Understanding the correlation between exposed surfaces and performances of controlled nanocatalysts can aid effective strategies to enhance electrocatalysis, but this is as yet unexplored for the nitrogen reduction reaction (NRR). Here, we first report controlled synthesis of well-defined Pt(3)Fe nanocrystals with tunable morphologies (nanocube, nanorod and nanowire) as ideal model electrocatalysts for investigating the NRR on different exposed facets. The detailed electrocatalytic studies reveal that the Pt(3)Fe nanocrystals exhibit shape-dependent NRR electrocatalysis. The optimized Pt(3)Fe nanowires bounded with high-index facets exhibit excellent selectivity (no N(2)H(4) is detected), high activity with NH(3) yield of 18.3 μg h(−1) mg(−1)(cat) (0.52 μg h(−1) cm(−2)(ECSA); ECSA: electrochemical active surface area) and Faraday efficiency of 7.3% at −0.05 V versus reversible hydrogen electrode, outperforming the {200} facet-enclosed Pt(3)Fe nanocubes and {111} facet-enclosed Pt(3)Fe nanorods. They also show good stability with negligible activity change after five cycles. Density functional theory calculations reveal that, with high-indexed facet engineering, the Fe-3d band is an efficient d-d coupling correlation center for boosting the Pt 5d-electronic exchange and transfer activities towards the NRR.