Engineering NiFe₂O₄ decorated with IrO₂ on plasma-treated iron foam for enhanced electrocatalytic hydrogen evolution

The study presents a robust plasma-assisted strategy for fabricating heterostructure electrocatalysts, addressing the persistent challenge of developing efficient hydrogen evolution reaction (HER) systems. A highly effective and durable NiFe₂O₄-IrO₂ electrocatalyst is successfully engineered on iron foam (FF) modified by dielectric barrier discharge (DBD) plasma (PFF). The plasma treated PFF substrate demonstrates critical advantages with 3D hierarchical architecture promoting electrolyte infiltration, strong interfacial bonding energy, and accelerated gas evolution kinetics. The optimized NiFe₂O₄-IrO₂/PFF exhibits exceptional HER performance with ultralow overpotentials of 24/222/310 mV at 10/100/300 mA cm⁻², respectively, outperforming most reported Fe-based catalysts. Furthermore, the catalyst demonstrates excellent stability, retaining its activity over 100 h at 10 mA cm^-2. Additionally, density functional theory (DFT) calculations reveal that the synergistic effect between NiFe₂O₄ and IrO₂ on the PFF substrate contributes to the outstanding HER performance. The study offers an effective strategy for developing highly active electrocatalysts, presenting a promising approach for advancing HER technologies.