Anion-exchange membrane fuel cell (AEMFC) is a cost-effective hydrogen-to-electricity conversion technology under a zero-emission scenario. However, the sluggish kinetics of the anodic hydrogen oxidation reaction (HOR) impedes the commercial implementation of AEMFCs. Here, we develop a Pd single-atom-embedded NiN catalyst (Pd/NiN) with unconventional PdNi trimer sites to drive efficient and durable HOR in alkaline media. Integrating theoretical and experimental analyses, we demonstrate that dual PdNi sites achieve a "*H on PdNi-H + *OH on PdNi-H" adsorption mode, effectively weakening the overstrong *H and *OH adsorptions on pristine NiN. Owing to the unique coordination mode and atomically dispersed catalytic sites, the resulting Pd/NiN catalyst delivers a high intrinsic and mass activity together with excellent antioxidation capability and CO tolerance. Specifically, the HOR mass activity of Pd/NiN reaches 7.54 A mg at the overpotential of 50 mV. The AEMFC employing Pd/NiN as the anode catalyst displays a high power density of 31.7 W mg with an ultralow anode precious metal loading of only 0.023 mg cm. This study provides guidance for the design of high-performance alkaline HOR catalytic sites at the atomic level.
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http://dx.doi.org/10.1021/jacs.4c17605 | DOI Listing |
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