Orbital Hybridization at Au-O-Zr Interface Promotes Synergistic Single-Atom/Cluster Catalysis for Durable Zinc-Air...

Single-atom catalysts (SACs) are fundamentally limited by the activity-stability trade-off in oxygen electrocatalysis, primarily due to the high surface energy and aggregation tendency of isolated metal atoms. Herein, we develop a low-temperature (200 °C) in situ thermal anchoring strategy to construct a hybrid Au catalyst (Au ACSA-ZrO₂) comprising atomically dispersed Au single atoms and clusters stabilized on ZrO₂ nanoparticles. This mild yet effective process induces strong metal-support interactions (SMSI), leading to the formation of covalent Au-O-Zr interfacial bonds. These bonds effectively inhibit atomic migration and coalescence while simultaneously promoting interfacial charge transfer. Electronic coupling between Au single atoms and adjacent clusters induces significant hybridization between O 2p and Zr 4d orbitals, which modulates the local coordination environment and optimizes the adsorption energetics of oxygenated intermediates, thereby accelerating both oxygen reduction and evolution reaction kinetics. When applied in a Zn-air battery, this dual-site catalyst exhibits exceptional durability with 71.07% round-trip efficiency and negligible decay over 260 h of continuous cycling, demonstrating that precise orbital interaction, achievable even at low synthesis temperatures, is crucial for high-performance bifunctional electrocatalysis.