Mo, Fe Co-doped Ni3S2 Nanorod Arrays on Nickel-Iron Foam: A High-Performance Bifuncational Catalyst for Overall Water Splitting

The design of efficient and cost-effective bifunctional catalysts to replace precious metal-based catalysts remains a critical challenge in electrocatalytic water splitting. Herein, we report a Mo-Fe co-doped Ni 3 S 2 nanorod arrays grown on a nickel-iron foam substrate via a facile hydrothermal synthesis. This dual metal-doped nanorod structure synergistically modulates the electronic structure while maximizing accessible active sites, endowing the Mo-Fe-Ni 3 S 2 electrode with exceptional bifunctional activity for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline media. The resulting Mo-Fe-Ni 3 S 2 electrode requires only 180   mV for HER and 275   mV for OER at a current density of 100   mA   cm −2 , coupled with long-term stability exceeding 50   h. Remarkably, when integrated into a single-stack cell for practical application, the Mo-Fe-Ni 3 S 2 electrode exhibits outstanding performance, achieving a current density of 100   mA   cm −2 at a potential of 1.87   V and showing no potential degradation after 100   hours of continuous operation at 100   mA   cm −2 . This work not only presents a high-performance bifunctional catalyst but also provides fundamental insights into the design of advanced electrocatalysts through rational heteroatom doping strategies.