Amorphous heterogeneous NiFe-LDH@Co(OH)2 supported on nickel foam as efficient OER electrocatalysts

Oxygen evolution reaction (OER) is considered as the bottleneck of electrochemical water splitting because of its sluggish kinetics. Therefore, the design and synthesis of highly active, low-cost, and stable electrocatalysts for the OER is the greatest challenge in electrochemical water splitting. Here, an amorphous heterogeneous NiFe-LDH@Co(OH)2@NF with abundant active sites is fabricated by a step-wise electrodeposition technique. Firstly, Co(OH)2 is directly deposited onto nickel foam (NF) substrate by a electrodeposition technique. Secondly, NiFe-layered double hydroxide (NiFe-LDH) is further covered on the surface of Co(OH)2 to obtain the heterogeneous NiFe-LDH@Co(OH)2@NF electrocatalyst. The thickness of NiFe-LDH can be controlled by changing the time of electrochemical deposition. Benefiting from the amorphous structure and the positive synergies between NiFe-LDH and Co(OH)2, the optimized NiFe-LDH@Co(OH)2@NF-300 shows high electro-catalysis activity. In the 1 M KOH solution, the overpotential for OER is only 130 mV (at 10 mA cm−2). Remarkably, serving as a bifunctional electrode in alkaline electrolyzer, it only needs 1.6 V to reach the current density of 10 mA cm−2. The work provides a simple and viable technical solution for fabricating non-noble electrocatalysts with excellent performance for electrochemical water splitting.