Ionic-Liquid-Assisted One-Step Synthesis of CoO Nanosheets as Electrocatalysts for Oxygen Evolution Reaction

[Image: see text] The sluggish oxygen evolution reaction (OER) hinders the development of electrocatalytic water splitting for energy conversion and storage. Therefore, it is imperative to explore the cost-effective and highly efficient noble-metal-free electrocatalysts for OER. Herein, we are introducing such OER electrocatalyst based on Co, fabricated through an ionic-liquid-assisted one-step synthesis, where ionic liquid played a dual role as solvent cum structure-directing agent. Besides possessing large-accessible surface area and numerous active sites, the as-prepared stable CoO nanosheets exhibited excellent electrochemical activity through establishing an extensive contact with the electrolyte. Under alkaline conditions, the overpotential to achieve a current density of 10 mA cm(–2) is only 320 mV, and the Tafel slope is as small as 70 mV dec(–1). Thus, our work provides a new pathway for designing and engineering the highly efficient non-noble metal OER electrocatalysts by using ionic liquids.