Cobalt, Ferrum Co‐Doped Ni3Se4 Nano‐Flake Array: An Efficient Electrocatalyst for the Alkaline Hydrogen Evolution and Overall Water Splitting

Abstract

Herein, Co, Fe co‐doped Ni3Se4 nano‐flake array (Ni0.62Co0.35Fe0.03)3Se4) was prepared on conductive carbon cloth by a two‐step hydrothermal method. XRD and EDX analysis show that the nanosheets are monoclinic Ni3Se4, and Co, and Fe were doped into the lattice of Ni3Se4. Electrochemical tests showed that Co, Fe co‐doping can effectively improve the hydrogen evolution activity of Ni3Se4 in acidic and alkaline environment. When the current density of (Ni0.62Co0.35Fe0.03)3Se4/CC is 10 mA/cm2 in 1 M KOH solution, the overpotentials of hydrogen evolution and oxygen evolution are 87 mV and 53.9 mV, respectively, and the Tafel slopes are 122.6 and 262 mV/dec. The electrochemical active area test (ECSA) and the polarization curve test further show that (Ni0.62Co0.35Fe0.03)3Se4/CC has a larger electrochemical active area (34.8 mF/cm2), lower electrolytic potential (0.9 V at 10 mA/cm2) and better stability. Therefore, the novel bifunctional catalyst synthesized by a simple method is a promising candidate for large‐scale industrial water electrolysis.