Interface engineering on super-hydrophilic amorphous/crystalline NiFe-based hydroxide/selenide heterostructure nanoflowers for accelerated industrial overall water splitting at high current density.

Designing heterojunction catalysts with energy effects at the interface, particularly combining the surface structure advantages of super-hydrophilic interfaces with the high activity advantages of bimetal synergistic optimisation, is the key to developing economical and efficient industrial electrocatalytic water-splitting catalysts. In this study, a coupled nanoflower-like NiFe(OH)/(Ni, Fe)Se heterostructure catalyst supported on Ni foam (NF) (NFSe@NFOH/NF) was designed and successfully prepared using hydrothermal and electrodeposition strategies. Owing to the electron interaction at the heterogeneous amorphous (NFOH)/crystalline (NFSe) interface and the bimetallic synergistic effect of Ni and Fe, the prepared NFSe@NFOH/NF exhibited excellent and stable oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) catalytic properties, with low overpotentials of 214/276 mV at 100 mA⋅cm and 262/340 mV at 500 mA⋅cm.