Pt-Based Ternary Alloy on Nanohoneycomb Nitrogen-Doped Carbon 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 (n) 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.