Heterostructure arrays of (Ni,Co)Se2 nanowires integrated with MOFs-derived CoSe2 dodecahedra for synergistically high-efficiency and stable overall water splitting

• (Ni,Co)Se 2 /CoSe 2 /NF heterostructure electrocatalyst was desinged for water splliting. • The (Ni,Co)Se 2 /CoSe 2 /NF exhibied superior bifunctional OER/HER catalytic performances. • The constructed overall water-splitting cell achieves 10 mA cm −2 at 1.56 V. • The component synergy is responsible for the high electrocatalytic activity. The green and pollution-free hydrogen produced by electrochemical water splitting as a clean energy carrier can effectively alleviate the energy crisis. Herein, we investigated and fabricated a unique heterostructure arrays of (Ni,Co)Se 2 nanowires integrated with the metal–organic frameworks-derived (MOFs) CoSe 2 dodecahedra on nickel foam (NF) as an effective binder-free electrode for water splitting. The as-synthesized (Ni,Co)Se 2 /CoSe 2 /NF electrocatalyst exhibits excellent electrochemical performance in alkaline solutions with HER and OER overpotentials as low as 65 mV and 255 mV, respectively, at a current density of 10 mA cm −2 as well as high stability. The alkaline electrolyzer for overall water splitting using (Ni,Co)Se 2 /CoSe 2 /NF as electrocatalyst requires only cell voltage of 1.56 V to drive a current density of 10 mA cm −2 and maintained without significant decay over 50 h. The unique heterostructure with abundant active sites and strong synergistic effect between (Ni,Co)Se 2 nanowires and CoSe 2 could modulate the electronic structure and enhance the charge transfer, thus contributing to high electrocatalytic activity. This study provides a suitable method and reference for optimizing the structure of bifunctional transition metal-based selenides to improve electrocatalytic water splitting performance.