Unveiling facet engineering of ultrathin Pt overlayers for enhanced ammonia oxidation reaction

초록

Utilizing ammonia for hydrogen production via ammonia oxidation reaction (AOR) remains a challenge owing to insufficient electrode performance and high cost of noble metal. Herein, we performed repeated self-terminated electrodeposition (SED) of Pt on Ni substrate to obtain Pt/Ni electrodes. The electron-deficient Ni sites prefer *OH adsorption and serve as a reservoir for NH3 dehydrogenation, thereby promoting NH3 adsorption on Pt sites. Additionally, this iterative process enabled precise regulation of the Pt loading mass. Pt5/Ni electrode exhibited the highest catalytic activity for AOR. Subsequently, immersing this electrode in various acid solutions resulted in surface morphologies with numerous well-defined pits, driven by the adsorption of different electrolyte ions. Specifically, etching in HNO3 led to a higher Pt(1 0 0) density, further enhancing the electrode's catalytic performance for AOR. Thus, this study offers a simple, fast, and spontaneous method for facet engineering ultrathin Pt overlayers on Ni substrate under ambient conditions. © 2024 Elsevier B.V.

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