Boosting the oxygen evolution of high-entropy (oxy)hydroxide epitaxially grown on high entropy alloy by lattice oxygen activation

The unique electronic structure and diverse elemental composition of high-entropy materials (HEMs) have already showcased remarkable properties in the realm of oxygen evolution reaction (OER). Despite this, the active sites and reaction pathways of HEMs have yet to be fully understood. Our findings indicate that the addition of Fe in HEMs results in a more positive valence state of metals, leading to the enhancement of the covalent characteristic of the M-O bond. Additionally, the predominant oxygen 2p orbitals near the Fermi level enables lattice oxygen to function as an OER center. Guided by theoretical calculations, we synthesized a nanoporous NiFeCoMnOOH (np-NiFeCoMnOOH) electrocatalyst exhibited a low overpotential of 194 mV at 10 mA cm−2 and long-term stability of 120 h at 100 mA cm−2. These results offer insights into the reaction mechanisms of HEM electrocatalysts and may guide future studies in designing high-entropy electrocatalysts with superior activity.