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

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.