Bifunctional poly(3,4-ethylenedioxythiophene) intercalation enables interlayer engineering in nickel-iron layered...

Layered double hydroxides (LDHs) are promising electrocatalysts for the oxygen evolution reaction (OER); however, restricted interlayer ion accessibility and poor intrinsic electronic conductivity remain persistent limitations of conventional LDH electrodes. Herein, poly(3,4-ethylenedioxythiophene) (PEDOT) intercalation is introduced as an interlayer engineering strategy for nickel-iron layered double hydroxides (NiFe-LDHs) through sequential anion exchange (CO₃^2-, Cl^-, and SO₄^2-), 3,4-ethylenedioxythiophene (EDOT) monomer intercalation, and in situ oxidative polymerization within the interlayer galleries. A nine-sample matrix enables systematic investigation of the effects of anion identity, EDOT intercalation, and PEDOT formation on the structural and electrochemical properties of NiFe-LDHs. X-ray diffraction (XRD) revealed a progressive basal-spacing expansion from 7.7 Å for NiFe-CO₃ LDH to 9.3 Å for NiFe PEDOT-SO₄ LDH. Among all samples, NiFe PEDOT-SO₄ LDH exhibited the best OER performance, requiring an overpotential of 285 ± 1 mV at 10 mA cm^-2 and a charge-transfer resistance of 2.4 ± 0.1 Ω. This work demonstrates conducting-polymer-based interlayer engineering as a promising strategy for simultaneously tailoring ion accessibility, electrochemically accessible surface/interface, and charge transport in LDH electrocatalysts for alkaline water electrolysis.