Synergistic doping and Interface engineering of Fe-NiP@V-NFOH p-n junctions for industrial alkaline water electrolysis.

The development of efficient and durable oxygen evolution reaction (OER) catalysts under industrial conditions remains a critical challenge for alkaline water electrolysis. Here, we report a heterostructured Fe-doped NiP@V-doped NiFe layered double hydroxide (LDH) catalyst (denoted as Fe-NiP@V-NFOH), synthesized through solid-phase phosphorization and electrochemical deposition. The p-n junction formed between the p-type Fe-NiP and n-type V-NiFe LDH induces interfacial charge redistribution, accelerating electron transfer and optimizing the adsorption of oxygenated intermediates. Density functional theory (DFT) calculations reveal that compared to pristine nickel‑iron layered double hydroxide (NiFe-LDH), the synergistic effect of heterointerface and doping engineering optimizes the adsorption energy of intermediate products, reducing the energy barrier from 1.74 eV to 1.45 eV. The catalyst achieved ultralow overpotentials of 241 and 260 mV at 500 and 1000 mA cm in 1 M KOH, respectively, and exhibited only negligible degradation after 2000 h at 1 A cm. When integrated into an alkaline electrolyzer (30 wt% KOH, 80 °C), the system required only 1.70 V to deliver 1000 mA cm and maintained stability over 200 h at 500 mA cm. This work demonstrates the synergistic role of doping and heterojunction engineering in designing robust OER catalysts, providing a viable pathway toward large-scale green hydrogen production.