Low-cost high entropy alloy (HEA) for high-efficiency oxygen evolution reaction (OER)

Oxygen evolution reaction (OER) is the key step involved both in water splitting devices and rechargeable metal-air batteries, and hence, there is an urgent need for a stable and low-cost material for efficient OER. In the present investigation, Co-Fe-Ga-Ni-Zn (CFGNZ) high entropy alloy (HEA) has been utilized as a low-cost electrocatalyst for OER. Herein, after cyclic voltammetry activation, CFGNZ-nanoparticles (NPs) are covered with oxidized surface and form high entropy (oxy) hydroxides (HE0s), exhibiting a low overpotential of 370 mV to achieve a current density of 10 mA/cm(2) with a small Tafel slope of 71 mV/dec. CFGNZ alloy has higher electrochemical stability in comparison to state-of-the art RuO2 electrocatalyst as no degradation has been observed up to 10 h of chronoamperometry. Transmission electron microscopy (TEM) studies after 10 h of long-term chronoamperometry test showed no change in the crystal structure, which confirmed the high stability of CFGNZ. The density functional theory (DFT) based calculations show that the closeness of d(p)-band centers to the Fermi level (E-F) plays a major role in determining active sites.This work highlights the tremendous potential of CFGNZ HEA for OER, which is the primary reaction involved in water splitting.

Automated summary

This study utilized CFGNZ high entropy alloy (HEA) as a low-cost electrocatalyst for OER, which showed efficient and stable characteristics after activation, highlighting its tremendous potential for applications.