Dynamic Interface Evolution of CeO₂–Supported Metal Single-Atom Catalysts under CO Oxidation

CeO₂-supported metal single-atom catalysts (SACs) exhibit distinct electronic properties and high atomic efficiency, making them promising candidates for catalytic applications. Under reaction conditions, such as CO oxidation, these catalysts show electronic structural and interfacial changes that directly impact their stability and activity. With an emphasis on applying the density functional theory, this review highlights the function of oxygen(O) vacancies, Ce³⁺/Ce⁴⁺ redox cycling, and strong metal–support interactions in stabilizing isolated atoms like Pt, Pd, Rh, and Au on the CeO₂ surface. All these elements work together to control resistance to sintering, adsorption behavior, and charge transfer. Temperature, gas environment, and pressure-induced reversible transitions between SAs, subnanoclusters, and oxidized species are discussed. Recent advances in situ and operando characterization techniques, combined with theoretical modeling, have deepened the understanding of local geometry (bond lengths and coordination), electronic structure (charge/spin states), and reaction mechanisms. This review highlights strategies to enhance metal dispersion and interface stability, including facet engineering, doping, and high-temperature treatments.