Take full advantage of hazardous electrochemical chlorine erosion to ultrafast produce superior NiFe oxygen evolution reaction electrode

Inexpensive yet efficient oxygen evolution reaction electrodes, working in high current densities, remain a pressing challenge for commercial hydrogen energy economy. NiFe (oxy)hydroxides are presented as strategic materials. Herein, a facile and industrially compatible electrochemical chlorine corrosion strategy for streamlined preparation of high-performance NiFe (oxy)hydroxide nanosheet arrays on commercial Ni/Fe foam not beyond 20 s with NaCl-based metal-free solutions is fathered firstly. An appealing anion competition-adsorption effect in anode-electrolyte interface boundaries is revealed that assumes strong dependence upon anion category and greatly influences chlorine corrosion behavior. We pioneeringly “counterplot” this mechanism to ingeniously convert into treasure a catastrophic chlorine-induced electrode erosion in electrochemical marine/saline water technology. Due to generating a self-consistent chlorine-phobic or -philic interface layer around anode surfaces assembled by anions, this anion-mediated mechanism enables rooting the morphologically/compositionally modulated NiFe hydroxide electrocatalysts onto substrates for the superior industrial current density-level oxygen evolution (over 800 h at 1 A cm−2 and 216 mV at 10 mA cm−2) or formulating the chlorine corrosion-immune electrolytes for the stable highly concentrated marine/saline water electrolysis (over 100 h at 0.3 A cm−2 in the 1 M NaCl + 1 KOH electrolyte). Given the rich anion chemistry, our trailblazing studies set a fresh stage towards the advanced oxygen evolution electrode or stable saline electrolysis for hydrogen production.