Acta Phys. -Chim. Sin. ›› 2011, Vol. 27 ›› Issue (12): 2849-2856.doi: 10.3866/PKU.WHXB20112849

• ELECTROCHEMISTRY AND NEW ENERGY • Previous Articles     Next Articles

Preparation of the Ni/NiCo2O4 Composite Electrode and Its Properties toward the Oxygen Evolution Reaction in Alkaline Media

BAO Jin-Zhen, WANG Sen-Lin   

  1. Department of Applied Chemistry, College of Materials Science and Engineering, Huaqiao University,Xiamen 361021, Fujian Province, P. R. China
  • Received:2011-06-20 Revised:2011-08-29 Published:2011-11-25
  • Contact: WANG Sen-Lin

Abstract: A NiCo2O4 spinel composite oxide was obtained by co-precipitation. A Ni/NiCo2O4 composite coating was prepared by composite electrodeposition in a Ni plating solution by mixing with NiCo2O4 powder. The best plating conditions for the composite electrodeposition were investigated by changing factors such as the plating bath pH and the cathode current density jk. The surface morphology, the NiCo2O4 content, and the structure of the Ni/NiCo2O4 composite coating were characterized by scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), and X-ray diffraction (XRD). As a result, the NiCo2O4 content in the Ni/NiCo2O4 composite coating was found to be the highest (30.6%, w) for a bath pH of 6.2 and a cathodic current density jk of 100 mA·cm-2. In 5 mol·L-1 KOH solution the electrocatalytic properties toward the oxygen evolution reaction (OER) of the Ni/NiCo2O4 composite electrode was studied using cyclic voltammetry, electrochemical steady-state polarization, and electrochemical impendence spectroscopy (EIS). Compared with the Ni electrode, the electrocatalytic properties for the OER of the Ni/NiCo2O4 composite electrode improved greatly and the apparent activation energy was reduced to 53.2 kJ·mol-1. The apparent exchange current density of the Ni/NiCo2O4 composite electrode toward the OER was 7 times as high as that of a nickel electrode. An electrochemical impendence spectroscopy analysis indicated that the oxygen evolution reaction of the Ni/NiCo2O4 composite electrode was co-controlled by an electrochemical step and a diffusion step. Constant potential electrolysis over extended periods for the OER shows that the stability of the Ni/NiCo2O4 composite electrode is good.

Key words: Ni/NiCo2O4, Spinel, Composite electrodeposition, Oxygen evolution electrode, Stability