Pulsed‐Laser Ablation for the Synthesis of High‐Entropy Alloy Aerogels Toward H ₂ O ₂ Production and Water Decolorization

ABSTRACT Electrosynthesis of H 2 O 2 is attractive for its environmental sustainability and cost‐effectiveness, yet is impeded by the sluggish reaction kinetics and low selectivity triggered by the competing 4e − pathway. Here, a model transition‐metal‐based multimetallic aerogel was designed using CrMnFeCoNi HEA nanoparticles from nanosecond‐pulsed laser synthesis in liquids, along with three exemplary quaternary systems without Co, Fe, and Ni, respectively. Among them, the resulting CrMnFeCoNi HEA aerogel exhibits the highest H 2 O 2 selectivity of 95% and the lowest transferred electron number of 2.1, as well as good stability of nearly 100% H 2 O 2 selectivity after 10k cycles. Furthermore, the as‐prepared CrMnFeCoNi aerogel reaches a maximum H 2 O 2 yield of 2.34 mmol h −1 and demonstrates an efficient decolorization ability for organic pollutants (e.g., Methylene blue or Rhodamine B). This outstanding performance is attributed to the synergetic effects of the various metals and the configurational entropy contribution, enabling a favored distribution of surface atom arrangements and optimal binding energies during electrochemical reactions. This work not only provides a novel perspective for manipulating HEA aerogels but also presents a promising alternative for industrial H 2 O 2 production and water treatment.