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

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. [Display omitted] •The CoNi hydroxide nanosheets on Ni foam were synthesized by electrodeposition.•The freestanding nanosheets show large surface area and low overpotential.•The Ni nanocones on Ni foam improved the stability and electrocatalytic properties.