Defect-Engineered Silver–Ceria Nanostructures: Linking Interfacial Chemistry to Catalytic and Antimicrobial Performance

Silver–ceria (Ag–CeO 2 ) nanostructures are an important class of metal–oxide materials whose catalytic and antimicrobial properties are strongly governed by Ag–ceria interfacial chemistry. Oxygen-deficient ceria, Ce 3+ /Ce 4+ states, Ag nuclearity and speciation, ceria morphology, and local coordination collectively influence charge redistribution, oxygen activation, ROS-related chemistry, and Ag dissolution/Ag + availability; however, their relative contributions depend strongly on material structure and operating environment, and no universal Ag–CeO 2 active site has been established. This review critically evaluates Ag–CeO 2 through an evidence-calibrated defect–interface–function framework that distinguishes direct Ag–CeO 2 observations from mechanistic principles transferred from other metal–ceria systems. Particular attention is given to synthesis-dependent interface engineering, the capabilities and limitations of defect-sensitive characterization, theoretical representations of heterogeneous interfaces, and quantitative structure–performance relationships. Available evidence indicates that oxygen-defect abundance alone is insufficient to predict functionality; defect location and accessibility, Ag nuclearity and coordination, surface termination, and working environment must also be considered. Proposed Agδ + –V o –Ce 3+ configurations are therefore treated as condition-dependent interfacial motifs rather than universally established active sites. Catalytic and antimicrobial functions share materials-level descriptors but diverge in their dominant physicochemical pathways and should not be reduced to a common mechanism. Accordingly, spatial organization and working-state accessibility of Ag–ceria interfaces, rather than defect maximization, emerge as more defensible design principles. Quantitative working-state characterization, standardized datasets, durability and Ag-leaching assessment, experimentally constrained modeling, and prospective experimental validation are identified as priorities for progress toward predictive Ag–CeO 2 interface engineering.