A Monolithic High‐Entropy Aerogel Anode for Stable and Low‐Overpotential Oxygen Evolution

ABSTRACT

The oxygen evolution reaction (OER) is pivotal to the energy transition. However, its sluggish multi‐electron kinetics and poor mass transport properties at high current densities have hindered its large‐scale implementation. In this work, we have developed a high‐entropy monolithic aerogel (HE‐AG) electrode that ingeniously integrates the electronic environmental diversity inherent to high‐entropy systems with the characteristic porous architecture of aerogels. This HE‐AG electrode demonstrates exceptional OER catalytic performance, achieving a current density of 500 mA cm ⁻² at an overpotential of merely 208 mV. Combined structural characterization and theoretical calculations reveal that the unique electronic environment of the HE‐AG is the key to independently modulating the multiple elementary electron‐transfer steps involved in the OER. Specifically, the precise tuning of the p ‐band center of the lattice oxygen effectively balances the binding strength between reaction intermediates and active sites. In situ Raman spectroscopy further elucidates the roles played by Cr and V within the high‐entropy system, demonstrating that their partial leaching during the OER significantly promotes the electrochemical reconstruction of the HE‐AG into the active metal oxyhydroxide phase. This synergistic strategy can be extended to serve as a general design rule for heterogeneous catalytic applications.