High entropy promoted active site in layered double hydroxide for ultra-stable oxygen evolution reaction electrocatalyst

In this study, high entropy layered double hydroxide (LDH) grown on nickel foam using a simple hydrothermal method is reported. The high entropy LDH consisting of five different non-noble transition metals of Fe, Ni, Co, Mn, and Cr (denoted as FeNiCoMnCr) exhibits an excellent OER activity in alkaline condition with a low overpotential of 218 mV at a current density of 50 mA cm⁻². It is superior to the binary, ternary, and quaternary-metal LDHs. We demonstrate that the high entropy FeNiCoMnCr LDH possesses ultra-stable electrochemical stability at a high current density of 400 mA cm⁻² for 600 h, which is the best stability of all the reported high entropy material electrocatalysts so far. The interaction among the multi-metal components along with the resulting electronic structure modulation facilitates the formation of highly-active γ-NiOOH species, significantly boosting catalytic activity; while the high entropy induced phase stability contributes to the superior durability.