Hollow urchin-like CoSe2 with high surface area as highly efficient electrocatalyst for oxygen evolution

• A novel hollow urchin-like CoSe 2 have been achieved using urchin-like Co(OH) 2 as template. • The annealed CoSe 2 with more active sites and ideal electronic structure can be used as highly efficient electrocatalyst for oxygen evolution. • This material only requires an overpotential value of 285 mV at the 10 mA·cm −2 current density. • This material shows excellent stability. CoSe 2 is considered as a terrific replacement for the noble metal oxides to accelerate the oxygen evolution reaction (OER). Herein, we develop a novel hollow urchin-like CoSe 2 using urchin-like Co(OH) 2 as template. The as-prepared CoSe 2 was treated at 300 °C. It displays low overpotential of 285 mV at the 10 mA·cm −2 current density, which is much lower than that of the treated flake CoSe 2 and untreated hollow urchin-like CoSe 2 . The cyclic voltammetry (CV) curves clearly demonstrated that the lager electrochemical active surface area of the CoSe 2 is attribute to the hollow urchin-like structure and the increase of the active site by heat treatment. Moreover, the heat treatment increases the number of antibonding orbitals of Co-Se, which is close to the ideal filling for OER. Therefore, the synergistic effect of the increased electrochemical active surface area and optimized electronic configuration enhances electrocatalytic activity of the catalyst. These results demonstrate the potential of hollow urchin-like CoSe 2 in the field of energy conversion and storage technologies, and open up a novel avenue to design of high surface area catalysts with excellent performance and durability as alternatives to the noble metal oxides.