Ultrathin Co3O4 Nanomeshes for the Oxygen Evolution Reaction

Ultrathin transition-metal-based nanomeshes can perfectly combine the advantages of two-dimensional (2D) ultrathin nanosheets and porous nanostructures, which have wide applications in energy storage and conversion. In this work, we present an etch-free one-step approach to directly synthesize the ultrathin Co3O4 nanomeshes (Co-UNMs) by employing a CoCl2/K3Co(CN)6 cyanogel as the reaction precursor. The 2D planar structural unit and solid properties of the cyanogel result in the preferential assembly of generated crystal nuclei at the solid–liquid interface (i.e., cyanogel–solution interface) in the 2D direction, which plays a key role in the formation of nanomeshes. The as-prepared Co-UNMs with 1.5 nm thickness and abundant pores have high surface area and numerous defect atoms, resulting in enhanced activity for the oxygen evolution reaction (OER) in alkaline media, such as a low overpotential of 307 mV at 10 mA cm–2, a small Tafel slope of 76 mV dec–1, and attractive durability in 1 M KOH electrolyte.