Abstract: The development of highly efficient nanozymes faces challenges of insufficient catalytic activity and low atom utilization. Atomically dispersed metal nanozymes have received widespread attention due to their high atomic utilization efficiency and exceptional catalytic activity. Bimetallic catalysts demonstrated enhanced catalytic performance owing to synergistic geometric and electronic effects arising from heterometallic interactions. Herein, we report an atomically dispersed palladium-iron bimetallic cluster nanozyme, in which fully exposed Pd clusters bonded to adjacent Fe atomic clusters are anchored onto defect-rich nanodiamond-graphene supports (PdFe/ND@G). The Pd-Fe interfacial sites fabricated in atomically dispersed bimetallic clusters deliver abundant oxygen activation sites for high-efficiency catalytic reactions and exhibit enhanced oxidase-like catalytic activity, demonstrating superior enzymatic activity and antibacterial performance compared to monometallic Pd and Fe clusters, while surpassing those of previously reported nanozymes. DFT calculations reveal that, compared to monometallic Pd clusters, atomically dispersed Pd-Fe clusters synergistically catalyze O₂ cleavage into OO* intermediates via Pd-Fe interfacial sites while exhibiting lower energy barriers, which is the critical factor for their enhanced enzyme-like activity. This study provides novel insights into constructing highly efficient atomically dispersed bimetallic cluster nanozymes.

Key words: Atomically dispersed catalyst, Fully exposed clusters, Pd-Fe interfacial sites, Oxidase-like activity, Antibacterial performance