Ion-Exchange Synthesis of Ternary FeCoNi-Layered Double Hydroxide Nanocage Toward Enhanced Oxygen Evolution Reaction and Supercapacitor

To cater for the development of clean hydrogen energy, an efficient oxygen evolution reaction catalyst is urgently needed to increase the efficiency of water splitting. A novel three-dimensional (3D) ternary transition metal hydroxide, FeCoNi-layered double hydroxide (FeCoNi-LDH) nanocage has been successfully synthesized by the cation exchange reaction using the metal–organic framework as a template. The obtained ternary FeCoNi-LDH nanocage displays excellent electrocatalytic activity, such as the low overpotential of 299 mV at j = 10 mA cm–2 in 1.0 M KOH electrolyte with a Tafel slope of 50 mV dec–1. Moreover, the FeCoNi-LDH nanocage could also be used as a high-performance electrode for supercapacitor, which presents a high specific capacity of 980 F g–1 at 1 A g–1 in 3.0 M KOH. More importantly, the electrode possesses a superb rate capability with 93% capacity retention even at a current density of 20 A g–1. These results manifest that FeCoNi-LDH has a wide prospect in the application in the energy conversion and storage fields.