Preparation of CoNi hydroxides and its performance of electro-catalytic oxygen evolution

• 1、College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 401331

Abstract：Amorphous Co/Ni double hydroxide (Co2Ni(OH)x) is prepared by the method of room-temperature ultrasonic bath coprecipitation using CoCl2, NiCl2 and Na3C6H5O7 as complexing agent. Morphology structure and composition of the samples are explored by filed emission scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, Raman spectrum, X-ray photoelectron spectroscopy, Linear Sweep Voltammetry, Chronopotentiometry, et al. The electro-catalytic oxygen evolution reaction activity and stability are evaluated in 0.1 M KOH. As a result, current density J is as high as 29.87 mA/cm2 (E = 0.900 V vs. HgO/Hg). It can efficiently catalyze OER in base with a current density of 10.00 mA cm-2 at an overpotential of 431 mV, exhibits favorable kinetics toward the OER with a Tafel slope of 79.70 mV/dec. The material's OER performance even surpasses the precious metal IrO2 when the loading is the same. It also has nice stability in alkaline electrolyte, maintains its activity (20 mA cm-2 ) for at least 8000 s.

Keywords： ultrasonic co-precipitation method Co2Ni(OH)x water electrolysis oxygen evolution reaction