High-entropy single-atom catalysts via spatial confinement synthesis for oxygen electrocatalysis and zinc–air batteries

Abstract

The development of efficient, stable, and noble-metal-free bifunctional oxygen electrocatalysts is a central challenge for advanced energy devices such as rechargeable zinc–air batteries (ZABs). While single-atom catalysts (SACs) show great promise, their performance is often limited by the scaling relationships of reaction intermediates. This study reports a five-metal (Mn, Fe, Co, Ni, Cu) high-entropy single-atom catalyst (HESAC) synthesized via a precise spatial confinement strategy designed to overcome this limitation. This strategy utilizes a ZIF-8-derived carbon support with a uniform pore size (∼1.88 nm) and ultrahigh specific surface area. The microporous confinement effect ensures that each pore accommodates only one acetylacetonate metal salt molecule, effectively preventing the migration and agglomeration of diverse metal atoms during pyrolysis and successfully enabling the construction of high-entropy single-atom sites. The resulting catalyst exhibits exceptional bifunctional oxygen electrocatalytic activity in alkaline electrolyte, surpassing the performance of commercial Pt/C for oxygen reduction reaction and IrO₂ for oxygen evolution reaction. This superior catalytic performance is readily translated into a high-performance rechargeable zinc–air battery, which demonstrates comprehensively better overall characteristics than its noble-metal-based counterpart. This work not only provides a novel synthetic pathway for designing high-performance HESAC but also demonstrates their significant potential in energy conversion and storage applications.