Fe, P dual-doping and phase boundary engineering of NiCo alloys: density functional theory (DFT)-optimized strategy for boosted water splitting

초록

The development of cost-effective, durable, and highly active bifunctional electrocatalysts is crucial for advancing overall water splitting. A one-step electrodeposition strategy is designed by DFT results to synthesize Fe and P co-doped NiCo face-centered cubic (fcc)/hexagonal close-packed (hcp) dual-phase alloy (Fe–Ni₁Co₂P@NiF), which demonstrates exceptional catalytic activity for both hydrogen and oxygen evolution reactions (HER/OER). The heterointerfaces between fcc and hcp phases and Fe, P doping enable efficient charge transfer and abundant active sites. DFT results show Fe and P doping optimize water adsorption, modulate the Ni/Co d-band center, and lower HER barriers. Moreover, the dopants act as preferential oxidation sites, preventing CoNi over-oxidation, enhancing OER activity. Electrochemical tests in 1 M KOH exhibit low overpotentials of 41 mV (HER) and 289 mV (OER) at 10 mA cm−2, achieving overall water splitting at voltages of 1.53 V and 1.65 V for 10 and 100 mA cm−2, respectively. It is worth noting that the catalyst maintains stability over 135 h at 50 mA cm−2. The enhanced performance stems from synergistic Fe, P doping, and phase boundary engineering, which collectively regulate electronic configurations and accelerate charge transfer. This work provides a promising approach for designing efficient electrocatalysts for practical water electrolysis applications. © 2025

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