Controllable synthesis of hollow NiSe2 spheres as an active electrocatalyst for hydrogen evolution reaction

The design of electrocatalysts with excellent performance and low cost is of great significance for the electrocatalytic water splitting. NiSe 2 has been widely concerned because of its suitable adsorption energy and adjustable electronic structure for hydrogen evolution reaction (HER). Here, a hollow spherical NiSe 2 catalyst was designed and prepared by the hydrothermal method. Thanks to the unique three-dimensional (3D) open configuration and favorable active components, it exhibits superior catalytic activity for HER. It delivers an overpotential of 330[Formula: see text]mV at the current density of 10[Formula: see text]mA[Formula: see text]cm[Formula: see text], corresponding to the Tafel slope of 128[Formula: see text]mV[Formula: see text]dec[Formula: see text]. This work demonstrates that the 3D hollow structure with large specific surface and rich internal space can effectively improve the mass transfer efficiency and electron transfer. This work may provide a controllable way for the design of hollow structure catalysts.