Na0.86Co0.95Fe0.05O2 Layered Oxide As Highly Efficient Water Oxidation Electrocatalyst in Alkaline Media.

Electrochemical energy storage and conversion technologies, such as water-splitting devices, rechargeable metal-air batteries, and regenerative fuel cells, are promising alternatives to traditional nonrenewable energy systems. Given the sluggish oxygen evolution reaction (OER) in the above renewable-energy technologies, the development of efficient OER electrocatalysts with high performance is of great importance. Here, we demonstrate a layer-structured oxide Na0.86Co0.95Fe0.05O2 (NCF0.05) as a novel electrocatalyst for efficient water oxidation in alkaline media. NCF0.05 shows enhanced performance, including lower overpotential, lower Tafel slope and better stability than the parent Na0.86CoO2 (NC). Especially, the OER performance of NCF0.05 is comparable to the state-of-the-art IrO2 catalyst. This enhanced catalytic activity of NCF0.05 may be ascribed to the unusual synergistic interplay between Fe and Co. A possible dual-metal-site mechanism was also proposed for OER on NCF0.05.