Quasi-Parallel NiFe Layered Double Hydroxide Nanosheet Arrays for Large-Current-Density Oxygen Evolution Electrocatalysis.

Abstract

Designing advanced electrocatalysts for oxygen evolution at large current density (>500 mA cm-2 ) is critical to practical water splitting applications. Herein, a novel quasi-parallel NiFe layered double hydroxide (NiFe LDH) nanosheet arrays with pattern alignment on Ni foam was developed. The initial α-Ni(OH)2 layer induced effective coprecipitation between Ni2+ and Fe3+ for the formation of LDH phase, guaranteeing the electronic pulling effect among metal cations and enhancing the interaction between active materials and substrate for excellent adhesion and electrical conductivity. Quasi-parallel NiFe LDH nanoarrays exhibited outstanding oxygen evolution activity with a small Tafel slope of 30.1 mV dec-1 and overpotentials of 196, 255, and 284 mV at a current density of 10, 500, and 1000 mA cm-2 in 1.0 m KOH solution, respectively, and high stability over 40 h at 750 mA cm-2 . This work presents a new strategy towards fabricating electrode materials with exceptional performance.