Surface immobilization of single atoms on heteroatom-doped carbon nanospheres through phenolic-mediated interfacial anchoring for highly efficient biocatalysis

Single-atom catalysts (SACs) dispersed on support materials exhibit exceptional catalytic properties that can be fine-tuned through interactions between the single atoms and the support. However, selectively controlling the spatial location of single metal atoms while simultaneously harmonizing their coordination environment remains a significant challenge. Here, we present a phenolic-mediated interfacial anchoring (PIA) strategy to prepare SACs with Fe single atoms anchored on the surface of heteroatom-doped carbon nanospheres. Briefly, by exploiting metal-phenolic networks (MPNs) for surface coating and phloroglucinol-induced polymerization for support precursor formation, we successfully anchored Fe single atoms at the interface between the MPN layer and the support surface. Moreover, this anchoring strategy effectively prevents Fe species from clustering or migrating toward the interior of the support during thermal treatment, resulting in atomically dispersed FeN₃P-SAC that exhibits a high metallic utilization efficiency and comparable peroxidase-like catalytic activity and kinetics to natural enzymes. As a proof-of-concept demonstration, FeN₃P-SAC could effectively block the growth of tumor cells in vitro by combining excellent tumor penetration and the ability to activate chemodynamic and photothermal effects synergistically. This work advances the development of highly active SACs with MPN-based nanotechnology, providing a promising approach for nanocatalytic tumor therapy.