Nitrogen-Doped Sponge Ni Fibers as Highly Efficient Electrocatalysts for Oxygen Evolution Reaction
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ARTICLE
Cite as Nano-Micro Lett. (2019) 11:21 Received: 26 January 2019 Accepted: 22 February 2019 © The Author(s) 2019
https://doi.org/10.1007/s40820-019-0253-5
Nitrogen‑Doped Sponge Ni Fibers as Highly Efficient Electrocatalysts for Oxygen Evolution Reaction Kaili Zhang1, Xinhui Xia1,6 *, Shengjue Deng1, Yu Zhong1, Dong Xie2, Guoxiang Pan3, Jianbo Wu4, Qi Liu5, Xiuli Wang1, Jiangping Tu1 * * Xinhui Xia, [email protected]; Jiangping Tu, [email protected] State Key Laboratory of Silicon Materials, Key Laboratory of Advanced Materials and Applications for Batteries of Zhejiang Province, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, People’s Republic of China 2 Guangdong Engineering and Technology Research Center for Advanced Nanomaterials, School of Environment and Civil Engineering, Dongguan University of Technology, Dongguan 523808, People’s Republic of China 1
3
4 5
6
Department of Materials Chemistry, Huzhou University, Huzhou 313000, People’s Republic of China Zhejiang Provincial Key Laboratory for Cutting Tools, Taizhou University, Taizhou 318000, People’s Republic of China Department of Physics, City University of Hong Kong, Kowloon 999077, Hong Kong Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), College of Chemistry, Nankai University, Tianjin 300071, China
HIGHLIGHTS
• Freestanding N-doped sponge Ni micro/nanofibers exhibit a porous sponge structure. • An N-doping strategy is adopted to optimize the catalytic activity. • γ-NiOOH is identified as active phase by XPS and NEXAFS analyses.
tured metal electrocatalysts for oxygen evolution reaction (OER) is
a particularly significant and challenging target. Herein, we report a 3D porous sponge-like Ni material, prepared by a facile hydrothermal method and consisting of cross-linked micro/nanofibers, as an integrated binder-free OER electrocatalyst. To further enhance the electrocatalytic
Overpotential (V)
ABSTRACT Controllable synthesis of highly active micro/nanostruc-
NF −1 Dec
0.4
71 mV
−1
Dec 66 mV -NF N c−1 40 mV De SN
0.2
−1
0.0 −0.5
33 mV Dec N-SN
0.0
0.5
1.0
1.5
Log current density (mA cm−2)
performance, an N-doping strategy is applied to obtain N-doped sponge Ni (N-SN) for the first time, via N H3 annealing. Due to the combination of the unique conductive sponge structure and N doping, the as-obtained
N-SN material shows improved conductivity and a higher number of active sites, resulting in enhanced OER performance and excellent stability. Remarkably, N-SN exhibits a low overpotential of 365 mV at 100 mA cm−2 and an extremely small Tafel slope of 33 mV dec−1, as well as superior long-term stability, outperforming unmodified sponge Ni. Importantly, the combination of X-ray photoelectron spectroscopy and near-edge X-ray adsorption fine structure analyses shows that γ-NiOOH is the surface-active phase for OER. Therefore, the combination of conductive sponge structure and N-doping modification opens a new avenue for fabricating new types of high-
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