In situ inducing CoFe LDH to nanosheet arrays as efficient superaerophobic electrocatalysts for anion exchange membrane water electrolysis

Design of efficient non-precious metal electrodes for anion exchange membrane water electrolysis (AEMWE) is an ongoing challenge. We in situ constructed a CoFe layered double hydroxide nanosheet array (CoFe LDH-NS array) on nickel foam (NF). Only 278 mV of low overpotential was required for the electrode to achieve a current density of 1000 mA·cm⁻² for oxygen evolution reaction (OER) and stable operation for over 200 h. The high catalytic activity, mechanical stability as well as electrical conductivity could be ascribed to the intimate interfacial contact between NF substrate with NiS intermediate layer and CoFe LDH. Moreover, the unique superaerophobic surface of the NS arrays promoted the release of the bubble and the re-engagement of the electrolyte with the active sites. In situ Raman results certified that in the OER process, CoOOH was the true active phase of the catalyst. In AEMWE tests, CoFe LDH-NS arrays||Pt/C/carbon paper (CP) arrays outperformed commercial IrO₂ at 80 °C and 1.62 V to actuate 1 A·cm⁻² and stable operating over 1500 h. This morphology-dependent enhancement strategy may lead to new references for efficient electrode design for the next generation of AEMWE.