Acta Phys. -Chim. Sin. ›› 2022, Vol. 38 ›› Issue (6): 2107005.doi: 10.3866/PKU.WHXB202107005

Special Issue: Surface and interface engineering for electrochemical energy storage and conversion

• ARTICLE • Previous Articles     Next Articles

Surface Modification of NiCo2O4 Nanowires using Organic Ligands for Overall Water Splitting

Ke Sun, Yongqing Zhao, Jie Yin, Jing Jin, Hanwen Liu, Pinxian Xi()   

  • Received:2021-07-02 Accepted:2021-08-13 Published:2021-08-30
  • Contact: Pinxian Xi E-mail:xipx@lzu.edu.cn
  • About author:Pinxian Xi, Email: xipx@lzu.edu.cn
  • Supported by:
    the National Natural Science Foundation of China(21931001);the National Natural Science Foundation of China(21922105);the National Natural Science Foundation of China(51771085);the National Natural Science Foundation of China(51801088);the Special Fund Project of Guiding Scientific and Technological Innovation Development of Gansu Province(2019ZX-04);the 111 Project(B20027);the Fundamental Research Funds for the Central Universities(lzujbky-2021-pd04);the Fundamental Research Funds for the Central Universities(lzujbky-2021-sp41);the Fundamental Research Funds for the Central Universities(lzujbky-2021-it12);the Fundamental Research Funds for the Central Universities(lzujbky-2021-37);the China Postdoctoral Science Foundation(2021M691375);the China National Postdoctoral Program for Innovative Talents(BX20200157)

Abstract:

Bifunctional electrocatalysts in alkaline media play an important role in the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), owing to the considerable influence of water splitting in the green energy sector. Herein, we present surface-modified NiCo2O4 nanowires (NWs) with rich defects as a highly efficient overall water splitting electrocatalyst in alkaline media, where the surface modification is accomplished using organic ligands. X-ray photoelectron spectroscopy reveals that the increase in the Co2+/Co3+ ratio is responsible for the excellent bifunctional electrocatalytic performance of the surface-modified NiCo2O4 NWs. As expected, benefiting from the organic ligand-dominated surface modification, the optimized NiCo2O4 NWs can display an overpotential of only 83 mV for the HER and 280 mV for the OER, with a current density of 10 mA·cm-2 in 1.0 mol·L-1 KOH solution. More importantly, the NiCo2O4 NWs surface-modified using organic ligands exhibit outstanding performance for overall water splitting, with a voltage of 2.1 V and current density of 100 mA·cm-2, and also maintain their activity for at least 15 h. The present work highlights the importance of increasing the content of Co2+ in the spinel structure of NiCo2O4 NWs for enhancing their performance in overall water splitting.

Key words: Bifunctional electrocatalyst, Organic ligand, Interface, Surface modified nanowire, Water splitting

MSC2000: 

  • O646