Interfacial engineering of high-curvature NiFe nanocone arrays for accelerated oxygen evolution via tip-induced electric field and rapid bubble detachment.

Abstract

In gas-evolving electrocatalysis, the trade-off between mass transfer polarization and intrinsic activity remains a fundamental bottleneck. This work reports the interfacial engineering of high-curvature NiFe bimetallic nanocone arrays (NiFe-HC@NF) via a facile cathodic electrodeposition strategy. Finite element method (FEM) simulations reveal that the high-curvature tips trigger a strong localized electric field, which drives the directional migration and enrichment of OH- ions, thereby suppressing concentration polarization at the reaction interface. This physical enhancement is effectively integrated with the intrinsic Ni-Fe electronic synergistic effects, as verified by XPS, which optimize the surface electronic states for superior intrinsic kinetics. Furthermore, the unique 3D array configuration constructs a superhydrophilic and superaerophobic interface, ensuring ultrafast bubble detachment and maintaining effective active site exposure under vigorous gas-evolving conditions. As a result, the NiFe-HC@NF electrode delivers a low overpotential of 269.8 mV at 500 mA cm-2 and maintains remarkable structural and catalytic integrity for over 400 h at 100 mA cm-2. This study provides a compelling curvature-engineering strategy to break the mass-transport limitations in high-performance alkaline water electrolysis.