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Controllable structure reconstruction of nickel-iron compounds toward highly efficient oxygen evolution

Mahmood, Azhar ; Yu, Qiangmin ; Luo, Yuting ; Zhang, Zhiyuan ; Zhang, Chi ; Qiu, Ling ; Liu, Bilu

Nanoscale, 2020-05, Vol.12 (19), p.1751-1759 [Periódico revisado por pares]

England: Royal Society of Chemistry

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  • Título:
    Controllable structure reconstruction of nickel-iron compounds toward highly efficient oxygen evolution
  • Autor: Mahmood, Azhar ; Yu, Qiangmin ; Luo, Yuting ; Zhang, Zhiyuan ; Zhang, Chi ; Qiu, Ling ; Liu, Bilu
  • Assuntos: Composition ; Electrocatalysts ; Hydroxides ; Iron ; Iron compounds ; Nickel compounds ; Nickel ferrites ; Oxidation ; Oxygen evolution reactions ; Photoelectrons ; Spectrum analysis ; Synthesis ; Valence ; X ray absorption ; X ray photoelectron spectroscopy
  • É parte de: Nanoscale, 2020-05, Vol.12 (19), p.1751-1759
  • Notas: 10.1039/d0nr02254c
    Electronic supplementary information (ESI) available: Details of the experimental methods, instruments, SEM, XRD, XPS, STEM-EDX, HRTEM, and electrochemical measurements. See DOI
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    SourceType-Scholarly Journals-1
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  • Descrição: Nickel-iron (Ni-Fe) compounds have received ever-increasing interest because of their high performance for the oxygen evolution reaction (OER). However, the structure and composition of the active phase of Ni-Fe compounds are not yet understood. Rational design of Ni-Fe compounds with proper composition and exposed active sites is highly desirable to further improve their performance. Here we reported the synthesis of different Ni-Fe compounds by incorporating Fe into the Ni(OH) 2 lattice with controlled concentrations and obtained several products including Ni-Fe layered double hydroxides (LDHs) with different amounts of Fe and NiFe 2 O 4 . In addition, β-Ni(OH) 2 without Fe and α-Fe 2 O 3 without Ni have also been synthesized for comparison. Among these four Ni/Fe based compounds, we found that the two-dimensional (2D) Ni 0.8 Fe 0.2 -LDH nanosheets with a hexagonal shape manifest a highest OER activity with a lowest overpotential of 235 mV at 10 mA cm −2 , a smallest Tafel slope of 41 mV dec −1 and excellent stability over 24 h. In situ Raman, X-ray absorption spectroscopy and X-ray photoelectron spectroscopy show that the enhanced activity of Ni 0.8 Fe 0.2 -LDH is due to the increased oxidation state of Ni from Ni 2+ to Ni 3+ . Our findings demonstrate that the composition of Ni-Fe compounds influences the oxidizing ability of Ni and consequently their catalytic performance. We also reveal a strong correlation between the structure and oxidizing power of the Ni in Ni-Fe compounds and their OER activity, indicating that the well-engineered structure and Ni-site electronics are the primary origins of their OER activity. This work not only provides a promising guideline for the design and synthesis of Ni/Fe based compounds, but also highlights the crucial role of each component in enhancing the activity of these electrocatalysts. Structure optimized Ni 0.8 Fe 0.2 -LDH catalyst and corresponding OER performance.
  • Editor: England: Royal Society of Chemistry
  • Idioma: Inglês
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  • Realização: ABCD-USP USP   Logos de Redes Sociais: Freepik

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