Construction of Self-Supporting NiCoFe Nanotube Arrays Enabling High-Efficiency Alkaline Oxygen Evolution

Enhancing the intrinsic activity and modulating the electrode–electrolyte interface microenvironment of nickel-based candidates are essential for breaking through the sluggish kinetics limitation of the oxygen evolution reaction (OER). Herein, a ternary nickel–cobalt–iron solid solution with delicate hollow nanoarrays architecture (labeled as NiCoFe-NTs) was designed and fabricated via a ZnO-templated electrodeposition strategy. Owing to the synergistic nanostructure and composition feature, NiCoFe-NT presents desirable alkaline OER performance, with a η10 and η500 of 187 and 310 mV, respectively, along with favorable long-term durability. In-depth analyses identify the heterogeneous nickel-based (oxy)hydroxide species derived from the oxidative reconstruction acting as an active contributor for oxygen evolution. Impressively, the regulatory mechanism of the catalytic performance by a rationally designed nanostructure was elucidated by compressive analyses; that is, the faster gas release processes induced by nanotube arrays can modulate the heterogeneous interface states during OER, which effectively facilitates the electrochemical charge–mass transfer to promote the reaction kinetics. To assess the practical feasibility, an alkaline water electrolyzer and a CO2 electrochemical reduction flow cell were constructed by coupling the anodic NiCoFe-NTs and cathodic nickel phosphides (Ni2P-NF) and metallic Cu electrocatalysts, respectively, both of which achieved high-efficiency operation.