Graphene as an intermediary for enhancing the electron transfer rate： A free-standing Ni3S2@graphene@CogSs electrocatalytic electrode for oxygen evolution reaction

• Published in: 纳米研究：英文版 2018, Vol.11 (3), p.1389-1398
• Main Authors: Qiuchun Dong, Yizhou Zhang, Ziyang Dai, Peng Wang, Min Zhao, Jinjun Shao, Wei Huang, Xiaochen Dong
• Format: Article
• Language: English
• Subjects: 中间人; 转移率; 电子; 反应; 进化; 电极; 阳极电流密度; 氧
• ISSN: 1998-0124; 1998-0000

A highly active and stable oxygen evolution reaction （OER） electrocatalyst is critical for hydrogen production from water splitting. Herein, three-dimensional Ni3Sa@graphene@Co9S8 （Ni3S2@G@Co9S8）, a sandwich- structured OER electro-catalyst, was grown in situ on nickel foam; it afforded an enhanced catalytic performance when highly conductive graphene is introduced as an intermediary for enhancing the electron transfer rate and stability. Serving as a free-standing electrocatalytic electrode, Ni3S2@G@Co9S8 presents excellent electrocatalytic activities for OER： A low onset overpotential （2 mA·cm^-2 at 174 mV）, large anode current density （10 mA·cm^-2 at an overpotential of 210 mV）, low Tafel slope （66 mV·dec^-1）, and predominant durability of over 96 h （releasing a current density of N 14 mA·cm^-2 with a low and constant overpotential of 215 mV） in a 1 M KOH solution. This work provides a promising, cost-efficient electrocatalyst and sheds new light on improving the electrochemical performance of composites through enhancing the electron transfer rate and stability by introducing graphene as an intermediary.