Pt-Based TernaryAlloy on Nanohoneycomb Nitrogen-DopedCarbon Support for Highly Active and Stable Oxygen Reduction Reaction

The development of efficient and stable cathodic oxygen reduction reaction (ORR) catalysts is key to promoting the commercialization of proton-exchange membrane fuel cells (PEMFCs). In this paper, a series of ultralow-Pt ternary alloy catalysts supported on honeycomb nitrogen-doped carbon (PtM₁M₂/HNC, M₁, M₂= Fe, Co, Ni, and Cu) with a 2 wt % Pt loading were designed. Among them, PtFeCu/HNC exhibited the best ORR activity, 4e selectivity, stability, and methanol resistance under alkaline conditions, which is attributed to the abundant defects and high N content in the HNC support, Pt-based ternary alloy sites, and the optimal Pt alloy strain effect generated by Fe and Cu, which effectively regulate the oxygen binding energy strength. Moreover, compared to PtFeCu/NC, results showed that the excellent ORR catalytic activity of PtFeCu/HNC is also due to its well-structured HNC support with an abundant mesoporous structure. In 0.1 M KOH, PtFeCu/HNC exhibited an ORR peak potential of 0.946 and a half-wave potential of 0.918 V (vs. RHE), respectively, with an electron transfer number (<i>n</i>) ranging between 3.9 and 4.0. After stability and antimethanol tests, PtFeCu/HNC showed almost negligible activity loss. This work provides a strategy for constructing efficient and stable ultralow-Pt catalysts.