Engineering a Three-Dimensional Hierarchical Electrode: Synergistic Enhancement of Activity and Mass Transfer for Efficient Oxygen Evolution

Electrolytic water hydrogen production faces dual bottlenecks: low intrinsic activity of electrocatalysts and poor mass transfer due to bubble adhesion at high current densities. To address these issues, we introduce a synergistic material-structure design to fabricate an open periodic three-dimensional Fe-Ni 2 P@NCA electrode, which integrates compositional modulation with structural engineering. Iron-doped Ni 2 P nanosheets (Fe-Ni 2 P) are in situ -anchored onto a nickel microcolumn array substrate (NCA). Density functional theory reveals that Fe doping enhances surface hydroxylation, promoting the formation of an active surface under reaction conditions. The open channels between microcolumns ensure superior electrolyte flow and bubble detachment. This synergistic interplay between composition-induced activity enhancement and microstructure-enabled mass transfer gives the Fe-Ni 2 P@NCA electrode remarkable oxygen evolution reaction performance, achieving a low overpotential of 360 mV at a current density of 600 mA·cm −2 and stable operation for 1000 h at 500 mA·cm −2 . The electrode is fabricated via a scalable route combining thermal imprint lithography, microcurrent electroplating, and hydrothermal reactions, eliminating complex photolithography/etching processes. This study provides a holistic design approach for developing efficient and stable electrolysis electrodes based on the synergy between material composition, structure, and performance.