Terracing Oxyphilic Platinum Sustains High-Rate Ammonia Electrolysis and Fuel Cells.
basic_science · Level V
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- Record sourced from PubMed, PMID 41190948.
- Also identified by DOI 10.1002/adma.202514467.
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Abstract
The sluggish kinetics and catalyst poisoning of the ammonia oxidation reaction (AOR) pose technical barriers to adopting ammonia as a distributable carrier for green hydrogen and electricity. Herein, a class of PtIrRh nanowires (NWs, ≈1 nm diameter) is report with abundant terraces and oxyphilic doping for enhanced AOR electrocatalysis. It is first unravel, through size-dependent AOR activity, that well-coordinated terraces outperform under-coordinated steps on platinum, guiding the rational design of 1D architecture. The compositionally-optimized Pt<sub>86</sub>Ir<sub>5</sub>Rh<sub>9</sub> NWs achieve a mass activity of 324 A g<sup>-1</sup> <sub>PGM</sub> at 0.6 V, alongside an on-set potential (E<sub>on-set</sub>) of 0.41 V. Electrochemical studies coupling in situ attenuated total reflection Fourier transform infrared spectra establish voltammetry-accessible descriptors: surface oxyphilicity governs the E<sub>on-set</sub>, while nitrogenous adsorption strength dictates peak current density (j<sub>peak</sub>). In a membrane electrode assembly, the Pt<sub>86</sub>Ir<sub>5</sub>Rh<sub>9</sub> NWs enable ammonia electrolysis at 1 A cm<sup>-2</sup> with a cell voltage of 0.63 V-1 V lower than the typical value of water electrolysis, and drive a direct ammonia fuel cell to 339 mW cm<sup>-2</sup> at 0.4 V. The findings redefine Pt-based AOR catalyst design and advance ammonia-mediated hydrogen economy toward practicality.