Heterostructure engineering of self-supported bimetallic sulfide as an efficient bifunctional electrocatalyst for overall water splitting

The exploitation of effective bifunctional electrocatalysts for oxygen and hydrogen evolution reactions (OER, HER) is of great significance to hydrogen energy production via electrocatalytic water splitting. Herein, a self-supported Ni₃S₂/NiMo₂S₄-POM/NF hybrid heterostructure with uniform flower-like nanosheets and highly porous for overall water-splitting was synthesized via a scalable hydrothermal method followed by a vulcanization treatment. Significantly, the obtained three-dimensional porous heterostructure with high structural integrity ensures sufficient exposure of active sites and effectively adjusts the electronic structure for faster charge carrier dynamic to achieve enhanced reaction kinetics. The as-prepared Ni₃S₂/NiMo₂S₄-POM/NF achieves low overpotentials of 275 and 338 mV to deliver a current density of 100 mA cm⁻² for OER and HER. Furthermore, the assembled alkaline electrolyze comprised of Ni₃S₂/NiMo₂S₄-POM/NF for both anode and cathode exhibits an appealing voltage of 1.53 V at 10 mA cm⁻² with excellent long-term durability, implying notable catalytic activity of Ni₃S₂/NiMo₂S₄-POM/NF towards overall water-splitting. This work sheds light on a simple approach for synthesizing highly efficient electrocatalysts for water electrolysis.