Low-Coordination Trimetallic PtFeCo Nanosaws for Practical Fuel Cells.

Developing high-performance catalysts for fuel cell catalysis is the most critical and challenging step for the commercialization of fuel cell technology. Here 1D trimetallic platinum-iron-cobalt nanosaws (Pt FeCo NSs) with low-coordination features are designed as efficient bifunctional electrocatalysts for practical fuel cell catalysis. The oxygen reduction reaction (ORR) activity of Pt FeCo NSs (10.62 mA cm and 4.66 A mg at 0.90 V) is more than 25-folds higher than that of the commercial Pt/C, even after 30 000 voltage cycles. Density functional theory calculations reveal that the strong inter-d-orbital electron transfer minimizes the ORR barrier with higher selectivity at robust valence states. The volcano correlation between the intrinsic structure featured with low-coordination Pt-sites and corresponding electronic activities is discovered, which guarantees high ORR activities. The Pt FeCo NSs located in the membrane electrode assembly (MEA) also achieve very high peak power density (1800.6 mW cm ) and competitive specific/mass activities (1.79 mA cm and 0.79 A mg at 0.90 V cell voltage) as well as a long-term lifetime in specific H O medium for proton-exchange-membrane fuel cells, ranking top electrocatalysts reported to date for MEA. This work represents a class of multimetallic Pt-based nanocatalysts for practical fuel cells and beyond.