Cactus-like (Ni,Co)Se2 nanosheets with 3D structure decorated on the conductive substrate for efficient hydrogen evolution reaction

Transition metal selenides are a fascinating class of substitute for traditional noble metal electrocatalysts for hydrogen evolution reaction (HER). However, the monometallic selenides still have the disadvantages of low electroactive sites and electrical conductivity. To address such drawbacks, three-dimensional (3D) hierarchical nanostructures composed of bimetallic compounds have aroused great attention. In this study, cactus-like bimetallic nickel–cobalt nanosheets with a 3D nanostructure are successfully prepared on the surface of conductive substrate by a one-step hydrothermal reaction. Then a high-efficiency bimetallic catalyst ((Ni,Co)Se2/CFP) is obtained by a facile chemical vapor deposition. Benefiting from bimetallic components and the unique 3D structure, the cactus-like (Ni,Co)Se2/CFP only requires a low overpotential of 154 mV to reach the current density of 10 mA cm−2. The Tafel slope of (Ni,Co)Se2/CFP (67 mV dec-1) further shows that (Ni,Co)Se2/CFP has faster HER kinetics. Besides, the long-term stability test demonstrates the excellent durability of (Ni,Co)Se2/CFP in 0.5 M H2SO4. This research offers a useful technique and guide for improving the structure of bimetallic selenides based on transition metals to design high-efficient HER electrocatalysts.