Water-Plasma Assisted Synthesis of Oxygen-Enriched Ni–Fe Layered Double Hydroxide Nanosheets for Efficient Oxygen Evolution Reaction

Developing nonprecious and effective catalysts for electrochemical oxygen evolution reaction (OER) remains a critical challenge among energy conversion technologies. Herein, we developed a novel oxygen-enriched nickel–iron layered double hydroxide (NiFe-LDH) nanosheets electrocatalyst prepared by water-plasma assisted synthesis. The water-plasma engraved oxygen-enriched NiFe-LDH nanosheets possessed a large petal structure of ∼3 μm lateral size with plentiful pores distributed on each flak with 10 nm thicknesses, and a large BET surface area (151 m2 g–1). Profiting by enriched oxygen atoms and fast charge transfer, the oxygen-enriched NiFe-LDH nanosheets displayed a favorable electrocatalytic performance toward OER with a low Tafel slope of 74 mV dec–1 and an overpotential at 10 mA cm–2 for 310 mV in 1.0 M KOH. Such low overpotential was much smaller than initial NiFe-LDH nanosheets (360 mV), and even superior to commercial Ir/C electrocatalyst (370 mV). Sustainable and highly active full water splitting enabled by oxygen-enriched NiFe-LDH nanosheets could be further driven by solar cell or two alkali batteries.