Self-Supporting NiFe LDHs@Co-OH-CO₃ Nanorod Array Electrode for Alkaline Anion Exchange Membrane Water Electrolyzer

The development of efficient and durable electrodes for anion exchange membrane water electrolyzers (AEMWEs) is essential for hydrogen production. In this work, 2D NiFe layered double hydroxides (NiFe LDHs) nanosheets were grown on the 1D cobaltous carbonate hydroxide nanowires array (Co-OH-CO₃) and the unique 3D layered self-supporting nanorod array (NiFe LDHs@Co-OH-CO₃/NF) electrode was obtained. Importantly, we demonstrated an efficient and durable self-supporting NiFe LDHs@Co-OH-CO₃/NF electrode for oxygen evolution reaction (OER) and as the anode of the AEMWE. In a three-electrode system, the self-supporting NiFe LDHs@Co-OH-CO₃/NF electrode showed excellent catalytic activity for OER, with an overpotential of 215 mV at a current density of 20 mA·cm^-2 in 1 mol·L^-1 KOH, and the promising AEMWE performance upon using as the anode, with a current density of 0.5 A·cm^-2 at 1.72 V in 1 mol·L^-1 KOH at 70 ℃. The experimental results further revealed the outstanding performance of the electrode with the special morphological structure. The 3D layered structure of nanorod array electrode could effectively prevent the agglomeration of nanosheets, which is conducive to electron transfer and provides a large number of edge active sites for water electrolyzer.