Synergistic Antibacterial Activity of Ultralow Loading Atomically Dispersed Cu and Ag Clusters on CO ₂ -Derived Magnetic Carbon Nanofibers for Complete Inactivation of Escherichia coli and Staphylococcus aureus

The development of sustainable and highly efficient antibacterial materials is crucial for combating pathogenic contamination and antibiotic resistance. In this study, we report a synergistic antibacterial system featuring ultralow metal loadings of atomically dispersed Cu (1 wt %) and subnanometer Ag clusters (0.5 wt %) supported on magnetic carbon nanofibers (CNFs) synthesized via catalytic CO 2 hydrogenation. This approach integrates carbon capture and utilization (CCU) with the fabrication of high-performance functional materials. The Cu and Ag species were deposited through a spontaneous redox reaction with Ni nanoparticles encapsulated within the graphitic shells of the CNFs, eliminating the requirement for external reducing agents. Analysis of X-ray absorption spectroscopy confirmed that Cu exists as atomically dispersed divalent ions coordinated with oxygen-containing surface groups, while Ag forms metallic clusters with a low coordination number (CN = 2.2). Despite the ultralow metal consumption, the Cu−Ag/CNF composite achieved complete (100%) inactivation of both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus across a wide range of bacterial concentrations (10 5 −10 8 CFU/mL). The antibacterial activity is governed by a direct contact-induced membrane damage pathway. The synergistic effect is driven by the enhanced bacterial adhesion mediated by Cu species and subsequent irreversible structural collapse induced by Ag clusters. This work provides a robust, low-toxicity, and magnetically recoverable platform for water disinfection and environmental sterilization, highlighting the potential of CO 2 -derived nanomaterials in sustainable biotechnology.