24August2019

Nano-Micro Letters

Nitrogen-Doped Sponge Ni Fibers as Highly Efficient Electrocatalysts for Oxygen Evolution Reaction

Kaili Zhang1, Xinhui Xia1, *, Shengjue Deng1, Yu Zhong1, Dong Xie2, Guoxiang Pan3, Jianbo Wu4, Qi Liu5, Xiuli Wang1, Jiangping Tu1, *

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Nano-Micro Lett. (2019) 11: 21

First Online: 09 March 2019 (Article)

DOI:10.1007/s40820-019-0253-5

*Corresponding author. E-mail: helloxxh@zju.edu.cn (Xinhui Xia)

 

Abstract

 


Toc

Controllable synthesis of highly active micro/nanostructured 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 crosslinked micro/nanofibers, as an integrated binder-free OER electrocatalyst. To further enhance the electrocatalytic performance, an N-doping strategy is applied to obtain N-doped sponge Ni (N-SN) for the first time, via NH3 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-performance electrodes with application in electrochemical energy conversion devices.


 

Keywords

Oxygen evolution reaction; Electrocatalysis; Nickel; Sponge Structure; Electrochemical energy conversion

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