Defective layered NiFe double hydroxides anchored on self-supported CoNi-nitrogen doped carbon nanotube composite as advanced electrocatalyst for oxygen evolution reaction

Abstract

Oxygen evolution reaction (OER) is an essential process during electrochemical water-splitting. Due to its sluggish kinetics, low cost and highly efficient catalyst is invariably desired to decrease its overpotential for large-scale application. However, the overpotential of most advanced OER electrocatalysts is still more than 200 mV at the current density of 10 mA cm−2. In this work, we constructed active layered NiFe double hydroxides with cation defects on self-supported three-dimensional (3D) CoNi nitrogen-doped carbon nanotube composite substrate as integrated OER catalyst. Strikingly, electrochemical measurements showed that the optimized sample exhibited outstanding OER activity with low overpotentials of 178 and 268 mV at the current densities of 10 and 100 mA cm−2 in alkaline environment, alongside a good durability. The excellent OER performance was ascribed to the strongly synergistic effect of intrinsically active NiFe double hydroxide layers with abundant cation vacancies and 3D carbon nanotube composite substrate with good conductivity and various functional moieties, thus facilitating the electrocatalytic kinetic.