The effects of Al substitution and partial dissolution on ultrathin NiFeAl trinary layered double hydroxide nanosheets for oxygen evolution reaction in alkaline solution

• Published in: Nano energy 2017-05, Vol.35, p.350-357
• Main Authors: Liu, Haixia, Wang, Yanrong, Lu, Xinyao, Hu, Yi, Zhu, Guoyin, Chen, Renpeng, Ma, Lianbo, Zhu, Hongfei, Tie, Zuoxiu, Liu, Jie, Jin, Zhong
• Format: Article
• Language: English
• Subjects: Electrocatalysis in alkaline solution; Oxygen evolution reaction; Trinary layered double hydroxides; Two-dimensional layered materials; Ultrathin nanosheets
• ISSN: 2211-2855
• DOI: 10.1016/j.nanoen.2017.04.011

Recently, Ni–based layered double hydroxide (LDH) materials have attracted growing interest owing to the remarkable performance for oxygen evolution reaction (OER). Here we demonstrate the preparation of ultrathin Ni3FeAlx trinary LDH nanosheets with higher activity and stability than NiFe–LDH nanosheets for OER. The enhancement was derived from Al substitution, which increased the concentration of Ni3+ active sites on the catalyst surface. Besides, low-coordinated Ni and Fe atoms and defects were formed by partial etching/dissolution of Al3+ in alkaline solution, which further increased the activity towards OER. To improve the conductivity, Ni3FeAlx–LDH (x=0, 0.91, 1.27 or 2.73) nanosheets were also in-situ grown on three-dimensional-networked nickel foam. The binder-free Ni3FeAlx–LDH/Ni foam electrodes exhibited further improved catalytic performance compared to the electrodes made of powdery Ni3FeAlx–LDHs and nafion binder. The best OER performance was presented by Ni3FeAl0.91–LDH/Ni foam, showing a Tafel slope of 57mV/dec, a low overpotential (304mV) at the current density of 20mA/cm2, and a current density of 235mA/cm2 at 1.60V (vs. RHE). Furthermore, the Ni3FeAl0.91–LDHs/Ni foam electrode showed excellent long-term stability, maintaining a stable overpotential of 320mV at 20mA/cm2 after testing for 18h. [Display omitted] •Al-doping ultrathin Ni3FeAlx–LDH are fabricated by hydrothermal method.•The electrochemical OER performance of Ni3FeAlx–LDH is investigated.•The Ni3FeAlx–LDH exhibits remarkable electrocatalytic activity.•Possible mechanism for the OER of Ni3FeAlx–LDH is proposed.