Ni-Co layered double-hydroxide arrays on stainless steel substrate: Interfacial hydroxide layer enhanced electrocatalyst with high stability for oxygen evolution reaction in alkaline media

High-efficiency electrocatalysts for oxygen evolution reaction (OER) are highly desired during large-scale water electrolysis in hydrogen production. In this work, a commercial stainless steel (SS) mesh substrate is activated through an alternate acid etching/alkali-hydrothermal treatment to form an interfacial hydroxide layer. Subsequently, a seamless integrated electrode including Ni-Co layered double hydroxide (NiCo-LDH) nanoarrays and SS substrate is successfully synthesized. The pre-formed interfacial layer guides the growth of NiCo-LDH nanoarrays, and firmly connect NiCo-LDH nanoarray and stainless steel substrate, wherein a durable catalyst with high activity and low resistance nature for OER is constructed. The as-prepared integrated electrode delivers the low OER overpotential of 243 and 292 mV for 10 and 250 mA cm−2 current densities respectively, and excellent long-term durability over 100 h in 1 M KOH solution. Electrocatalysis studies reveal the role of the interfacial hydroxide layer on the growth and catalytic activity of NiCo-LDH nanoarrays, and structural stability in durability test.