Ni(OH)2/NiFe-PBA heterostructure nanoarrays with a surface-reconstructed Cl− repelling layer for efficient and stable seawater electrolysis

Abstract

A Ni(OH)₂/NiFe-PBA heterostructure nanoarray catalyst was designed as an efficient oxygen evolution reaction (OER) electrocatalyst for alkaline seawater electrolysis, achieving a current density of 10 mA cm⁻² at an overpotential of 292 mV. Notably, the Ni(OH)₂/NiFe-PBA catalyst undergoes in situ reconstruction during the OER, generating NiOOH as the active site and Fe(CN)₆³⁻ species as the Cl⁻ repelling layer, suppressing chloride oxidation and improving stability. This synergistic mechanism enhances catalytic stability, enabling sustainable operation for 1000 hours at 500 mA cm⁻², offering a viable strategy for hydrogen production from seawater.