Enhanced electrocatalytic properties of electrodeposited amorphous cobalt-nickel hydroxide nanosheets on nickel foam by the formation of nickel nanocones for the oxygen evolution reaction

Abstract

The catalytic performance of nanostructured bimetallic hydroxide nanosheets (NSs) on a Ni foam was investigated as a function of the Co/Ni concentration ratio. A facile but highly precise composition-controlled electrodeposition technique was employed to synthesize CoNi-layered double hydroxides (LDH) within tens of seconds; the 0.3/0.2 CoNi-LDH NSs showed the best current density (76.9 mA cm(-2) at 1 V (vs. Ag/AgCl)). However, the poor adhesion of the CoNi-LDH NSs on the Ni foam decreased the current density to 82% at 1 V (vs. Ag/AgCl) after 10 h. The manipulation of the surface of the Ni foam via the deposition of Ni nanocones (NCs) enhanced the long-term stability to 92.6% and led to an overpotential of 366 mV and a current density of 111.5 mA cm(-2) at 1 V (vs. Ag/AgCl) in 1 M KOH alkaline solution. Thus, the CoNi LDH NSs on the surface-modified Ni foam are a promisingly efficient and stable oxygen evolution reaction (OER) catalyst. (C) 2016 Elsevier B.V. All rights reserved.