Polydopamine-Coated Fe,Cr Co-Doped NiS₂ with M-N Coordination for Durable Oxygen Evolution

Developing low-cost, corrosion-resistant catalytic electrodes for the oxygen evolution reaction (OER) is essential for efficient and durable hydrogen production via anion exchange membrane water electrolysis (AEMWE). Herein, we report a polydopamine (PDA)-coated Fe,Cr codoped NiS₂ self-supporting electrode (PDA-Fe,Cr-NiS₂@NF). The nitrogen-rich functional groups of PDA establish robust M-N coordination bonds with active metal centers, thereby suppressing metal dissolution during anodic reconstruction. In parallel, the conductive PDA layer regulates interfacial electron redistribution and optimizes the hydrogen-bond network of interfacial water, lowering the OER activation energy. Its conformal protective layer further enhances catalyst stability. The optimized electrode delivers an OER overpotential of only 247 mV at 1 A cm^-2. When integrated as the anode with a PtNiC cathode in an AEMWE cell, the system reaches a current density of 1 A cm^-2 at only 1.737 V at 70 °C and operates stably for 1000 h, with a voltage decay rate of only 0.1 mV h^-1, an electrolysis efficiency of 71.96%, and an energy consumption of 4.157 kWh Nm^3- H₂. This work establishes a viable coordination-protection strategy for constructing durable, high-performance OER electrodes for industrial-scale water electrolysis.